Web Python Zeichenfolgenverarbeitung Beispiele

# Web Python String Split/Join Examples
# Comprehensive string splitting and joining operations

# 1. Basic Split Operations
from typing import List, Any

def split_by_space(text: str) -> List[str]:
    """
    Split string by whitespace

    Args:
        text: Input string

    Returns:
        List of words
    """
    return text.split()

def split_by_char(text: str, delimiter: str) -> List[str]:
    """
    Split string by character delimiter

    Args:
        text: Input string
        delimiter: Delimiter character

    Returns:
        List of parts
    """
    return text.split(delimiter)

def split_by_char_limited(text: str, delimiter: str, max_splits: int) -> List[str]:
    """
    Split string with maximum splits

    Args:
        text: Input string
        delimiter: Delimiter character
        max_splits: Maximum number of splits

    Returns:
        List of parts
    """
    return text.split(delimiter, max_splits)

def split_lines(text: str, keep_ends: bool = False) -> List[str]:
    """
    Split string into lines

    Args:
        text: Input string
        keep_ends: Keep line endings

    Returns:
        List of lines
    """
    if keep_ends:
        return text.split('\n')
    return text.splitlines()

def split_by_any(text: str, delimiters: str) -> List[str]:
    """
    Split by any of multiple delimiters

    Args:
        text: Input string
        delimiters: String of delimiter characters

    Returns:
        List of parts
    """
    import re
    return re.split(f'[{re.escape(delimiters)}]+', text)

# 2. Advanced Split Operations
def split_by_words(text: str) -> List[str]:
    """
    Split into words (removing punctuation)

    Args:
        text: Input string

    Returns:
        List of words
    """
    import re
    return re.findall(r'\b\w+\b', text)

def split_by_sentences(text: str) -> List[str]:
    """
    Split into sentences

    Args:
        text: Input string

    Returns:
        List of sentences
    """
    import re
    # Split by ., !, or ? followed by space or end
    sentences = re.split(r'(?<=[.!?])\s+(?=[A-Z])', text)
    return [s.strip() for s in sentences if s.strip()]

def split_and_keep(text: str, delimiter: str) -> List[str]:
    """
    Split but keep delimiters

    Args:
        text: Input string
        delimiter: Delimiter string

    Returns:
        List of parts with delimiters
    """
    import re
    pattern = f'({re.escape(delimiter)})'
    return re.split(pattern, text)

def split_by_length(text: str, length: int) -> List[str]:
    """
    Split string into fixed-length chunks

    Args:
        text: Input string
        length: Chunk length

    Returns:
        List of chunks
    """
    return [text[i:i + length] for i in range(0, len(text), length)]

def split_by_pattern(text: str, pattern: str) -> List[str]:
    """
    Split by regex pattern

    Args:
        text: Input string
        pattern: Regex pattern

    Returns:
        List of parts
    """
    import re
    return re.split(pattern, text)

def balanced_split(text: str, delimiter: str, num_parts: int) -> List[str]:
    """
    Split into balanced parts

    Args:
        text: Input string
        delimiter: Delimiter
        num_parts: Number of parts

    Returns:
        List of balanced parts
    """
    parts = text.split(delimiter)
    size = len(parts) // num_parts

    result = []
    for i in range(num_parts):
        if i == num_parts - 1:
            result.append(delimiter.join(parts[i * size:]))
        else:
            result.append(delimiter.join(parts[i * size:(i + 1) * size]))
    return result

# 3. Basic Join Operations
def join_with_char(strings: List[str], delimiter: str) -> str:
    """
    Join strings with delimiter

    Args:
        strings: List of strings
        delimiter: Delimiter string

    Returns:
        Joined string
    """
    return delimiter.join(strings)

def join_with_space(strings: List[str]) -> str:
    """
    Join strings with space

    Args:
        strings: List of strings

    Returns:
        Joined string
    """
    return ' '.join(strings)

def join_with_newline(strings: List[str]) -> str:
    """
    Join strings with newline

    Args:
        strings: List of strings

    Returns:
        Joined string
    """
    return '\n'.join(strings)

def join_with_tab(strings: List[str]) -> str:
    """
    Join strings with tab

    Args:
        strings: List of strings

    Returns:
        Joined string
    """
    return '\t'.join(strings)

def join_empty(strings: List[str]) -> str:
    """
    Join strings without separator

    Args:
        strings: List of strings

    Returns:
        Concatenated string
    """
    return ''.join(strings)

# 4. Advanced Join Operations
def join_with_index(strings: List[str], template: str = '{i}. {s}') -> str:
    """
    Join with index numbers

    Args:
        strings: List of strings
        template: Format template (i=index, s=string)

    Returns:
        Joined string with indices
    """
    return '\n'.join(template.format(i=i + 1, s=s) for i, s in enumerate(strings))

def join_as_pairs(strings: List[str], pair_delimiter: str = ': ', item_delimiter: str = '\n') -> str:
    """
    Join as key-value pairs

    Args:
        strings: List of even length
        pair_delimiter: Delimiter between pairs
        item_delimiter: Delimiter between items

    Returns:
        Joined string
    """
    pairs = []
    for i in range(0, len(strings), 2):
        if i + 1 < len(strings):
            pairs.append(f"{strings[i]}{pair_delimiter}{strings[i + 1]}")
    return item_delimiter.join(pairs)

def join_with_quotes(strings: List[str], quote: str = "'") -> str:
    """
    Join with quotes around each string

    Args:
        strings: List of strings
        quote: Quote character

    Returns:
        Joined string
    """
    return ', '.join(f"{quote}{s}{quote}" for s in strings)

def join_sentences(sentences: List[str]) -> str:
    """
    Join sentences properly

    Args:
        sentences: List of sentences

    Returns:
        Joined paragraph
    """
    return ' '.join(s.strip() for s in sentences if s.strip())

def wrap_and_join(strings: List[str], width: int = 80, indent: str = '') -> str:
    """
    Wrap and join text

    Args:
        strings: List of strings
        width: Line width
        indent: Indentation for each line

    Returns:
        Wrapped text
    """
    import textwrap
    text = ' '.join(strings)
    wrapped = textwrap.fill(text, width=width)
    if indent:
        wrapped = '\n'.join(indent + line for line in wrapped.split('\n'))
    return wrapped

# 5. Combined Operations
def split_and_join(text: str, split_delimiter: str, join_delimiter: str) -> str:
    """
    Split and rejoin with different delimiter

    Args:
        text: Input string
        split_delimiter: Original delimiter
        join_delimiter: New delimiter

    Returns:
        Rejoined string
    """
    return join_with_char(text.split(split_delimiter), join_delimiter)

def split_filter_join(text: str, delimiter: str, predicate) -> str:
    """
    Split, filter, and rejoin

    Args:
        text: Input string
        delimiter: Delimiter
        predicate: Filter function

    Returns:
        Filtered and rejoined string
    """
    parts = text.split(delimiter)
    filtered = [p for p in parts if predicate(p)]
    return delimiter.join(filtered)

def split_map_join(text: str, delimiter: str, func) -> str:
    """
    Split, transform, and rejoin

    Args:
        text: Input string
        delimiter: Delimiter
        func: Transform function

    Returns:
        Transformed and rejoined string
    """
    parts = text.split(delimiter)
    mapped = [func(p) for p in parts]
    return delimiter.join(mapped)

def split_trim_join(text: str, delimiter: str) -> str:
    """
    Split, trim whitespace, and rejoin

    Args:
        text: Input string
        delimiter: Delimiter

    Returns:
        Trimmed and rejoined string
    """
    parts = text.split(delimiter)
    trimmed = [p.strip() for p in parts]
    return delimiter.join(trimmed)

def split_unique_join(text: str, delimiter: str) -> str:
    """
    Split, remove duplicates, and rejoin

    Args:
        text: Input string
        delimiter: Delimiter

    Returns:
        Unique and rejoined string
    """
    parts = text.split(delimiter)
    seen = set()
    unique = []
    for p in parts:
        if p not in seen:
            seen.add(p)
            unique.append(p)
    return delimiter.join(unique)

# 6. Specialized Operations
def parse_csv_line(line: str) -> List[str]:
    """
    Parse CSV line (simple)

    Args:
        line: CSV line

    Returns:
        List of fields
    """
    import re
    # Handle quoted fields
    pattern = r'(?:^|,)(?:"([^"]*)"|([^",]*))'
    matches = re.findall(pattern, line)
    return [m[0] if m[0] else m[1] for m in matches]

def join_as_csv(fields: List[Any]) -> str:
    """
    Join as CSV line

    Args:
        fields: List of fields

    Returns:
        CSV string
    """
    import csv
    from io import StringIO
    output = StringIO()
    writer = csv.writer(output)
    writer.writerow(fields)
    return output.getvalue().rstrip('\n')

def parse_key_value(text: str, pair_delimiter: str = ',', kv_delimiter: str = '=') -> dict:
    """
    Parse key-value pairs

    Args:
        text: Input string
        pair_delimiter: Delimiter between pairs
        kv_delimiter: Delimiter between key and value

    Returns:
        Dictionary
    """
    result = {}
    pairs = text.split(pair_delimiter)
    for pair in pairs:
        if kv_delimiter in pair:
            key, value = pair.split(kv_delimiter, 1)
            result[key.strip()] = value.strip()
    return result

def join_key_value(pairs: dict, pair_delimiter: str = ', ', kv_delimiter: str = '=') -> str:
    """
    Join key-value pairs

    Args:
        pairs: Dictionary
        pair_delimiter: Delimiter between pairs
        kv_delimiter: Delimiter between key and value

    Returns:
        Joined string
    """
    return pair_delimiter.join(f"{k}{kv_delimiter}{v}" for k, v in pairs.items())

def create_table(rows: List[List[str]], header_delimiter: str = '|', row_delimiter: str = '\n') -> str:
    """
    Create table from rows

    Args:
        rows: List of rows (each row is list of cells)
        header_delimiter: Delimiter between cells
        row_delimiter: Delimiter between rows

    Returns:
        Table string
    """
    return row_delimiter.join(header_delimiter.join(row) for row in rows)

# 7. Utility Functions
def split_preserve_quotes(text: str, delimiter: str = ',') -> List[str]:
    """
    Split preserving quoted sections

    Args:
        text: Input string
        delimiter: Delimiter

    Returns:
        List of parts
    """
    import re
    pattern = f'{re.escape(delimiter)}(?=(?:[^"]*"[^"]*")*[^"]*$)'
    return re.split(pattern, text)

def join_for_url(params: dict) -> str:
    """
    Join parameters for URL

    Args:
        params: Dictionary of parameters

    Returns:
        URL query string
    """
    return '&'.join(f"{k}={v}" for k, v in params.items())

def split_url_params(url: str) -> dict:
    """
    Split URL parameters

    Args:
        url: URL string

    Returns:
        Dictionary of parameters
    """
    from urllib.parse import urlparse, parse_qs
    parsed = urlparse(url)
    return {k: v[0] if len(v) == 1 else v for k, v in parse_qs(parsed.query).items()}

# Usage Examples
def demonstrate_string_split_join():
    print("=== Web Python String Split/Join Examples ===\n")

    # 1. Basic split
    print("--- 1. Basic Split ---")
    text = "Hello World Python Programming"
    print(f"Text: {text}")
    print(f"Split by space: {split_by_space(text)}")
    print(f"Split by 'o': {split_by_char(text, 'o')}")
    print(f"Split limited: {split_by_char_limited(text, ' ', 2)}")

    # 2. Advanced split
    print("\n--- 2. Advanced Split ---")
    text = "word1,word2;word3|word4"
    print(f"Text: {text}")
    print(f"Split by delimiters: {split_by_any(text, ',;|')}")

    text = "Hello world. How are you? I'm fine!"
    print(f"\nText: {text}")
    print(f"Split sentences: {split_by_sentences(text)}")

    # 3. Basic join
    print("\n--- 3. Basic Join ---")
    words = ["Python", "is", "awesome"]
    print(f"Words: {words}")
    print(f"Join with space: '{join_with_space(words)}'")
    print(f"Join with dash: '{join_with_char(words, '-')}'")
    print(f"Join empty: '{join_empty(words)}'")

    # 4. Advanced join
    print("\n--- 4. Advanced Join ---")
    items = ["apple", "banana", "cherry"]
    print(f"Items: {items}")
    print(f"With index:\n{join_with_index(items)}")
    print(f"With quotes: {join_with_quotes(items)}")

    # 5. Combined operations
    print("\n--- 5. Combined Operations ---")
    text = "apple, banana, cherry, date"
    print(f"Original: {text}")
    print(f"Split and join: '{split_and_join(text, ', ', '; ')}'")

    text = "  apple  ,  banana  ,  cherry  "
    print(f"\nOriginal: '{text}'")
    print(f"Split trim join: '{split_trim_join(text, ',')}'")

    # 6. Specialized
    print("\n--- 6. Specialized Operations ---")
    text = "name=John,age=30,city=NYC"
    print(f"Text: {text}")
    parsed = parse_key_value(text)
    print(f"Parsed: {parsed}")
    print(f"Joined back: {join_key_value(parsed, ', ')}")

    # 7. CSV
    print("\n--- 7. CSV Operations ---")
    fields = ["John", "Doe", "30"]
    csv_line = join_as_csv(fields)
    print(f"CSV: {csv_line}")

    print("\n=== All String Split/Join Examples Completed ===")

# Export functions
export { split_by_space, split_by_char, split_by_char_limited, split_lines }
export { split_by_any, split_by_words, split_by_sentences, split_and_keep }
export { split_by_length, split_by_pattern, balanced_split }
export { join_with_char, join_with_space, join_with_newline, join_with_tab, join_empty }
export { join_with_index, join_as_pairs, join_with_quotes, join_sentences, wrap_and_join }
export { split_and_join, split_filter_join, split_map_join, split_trim_join, split_unique_join }
export { parse_csv_line, join_as_csv, parse_key_value, join_key_value, create_table }
export { split_preserve_quotes, join_for_url, split_url_params }
export { demonstrate_string_split_join }

# Web Python Regular Expression Examples
# Comprehensive regex pattern matching and string operations

# 1. Basic Pattern Matching
import re
from typing import List, Optional, Pattern, Match

def find_pattern(text: str, pattern: str) -> Optional[Match]:
    """
    Find first occurrence of pattern

    Args:
        text: Input text
        pattern: Regex pattern

    Returns:
        Match object or None
    """
    return re.search(pattern, text)

def find_all_patterns(text: str, pattern: str) -> List[str]:
    """
    Find all occurrences of pattern

    Args:
        text: Input text
        pattern: Regex pattern

    Returns:
        List of matches
    """
    return re.findall(pattern, text)

def match_pattern(text: str, pattern: str) -> bool:
    """
    Check if text matches pattern at start

    Args:
        text: Input text
        pattern: Regex pattern

    Returns:
        True if matches
    """
    return bool(re.match(pattern, text))

def full_match(text: str, pattern: str) -> bool:
    """
    Check if text fully matches pattern

    Args:
        text: Input text
        pattern: Regex pattern

    Returns:
        True if full match
    """
    return bool(re.fullmatch(pattern, text))

# 2. Search and Find
def search_with_flags(text: str, pattern: str, flags: int = 0) -> List[str]:
    """
    Search with regex flags

    Args:
        text: Input text
        pattern: Regex pattern
        flags: Regex flags (re.I, re.M, re.S, etc.)

    Returns:
        List of matches
    """
    return re.findall(pattern, text, flags)

def find_iter(text: str, pattern: str) -> List[Match]:
    """
    Find all matches as iterator

    Args:
        text: Input text
        pattern: Regex pattern

    Returns:
        List of match objects
    """
    return list(re.finditer(pattern, text))

def find_overlap(text: str, pattern: str) -> List[str]:
    """
    Find overlapping matches

    Args:
        text: Input text
        pattern: Regex pattern

    Returns:
        List of overlapping matches
    """
    matches = []
    for i in range(len(text)):
        m = re.match(pattern, text[i:])
        if m:
            matches.append(m.group())
    return matches

def search_multiline(text: str, pattern: str) -> List[str]:
    """
    Search in multiline mode

    Args:
        text: Input text
        pattern: Regex pattern

    Returns:
        List of matches
    """
    return re.findall(pattern, text, re.MULTILINE)

# 3. Validation Patterns
def validate_email(email: str) -> bool:
    """
    Validate email address

    Args:
        email: Email string

    Returns:
        True if valid
    """
    pattern = r'^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+.[a-zA-Z]{2,}$'
    return bool(re.fullmatch(pattern, email))

def validate_phone(phone: str) -> bool:
    """
    Validate phone number (US format)

    Args:
        phone: Phone string

    Returns:
        True if valid
    """
    pattern = r'^\(?([0-9]{3})\)?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$'
    return bool(re.fullmatch(pattern, phone))

def validate_url(url: str) -> bool:
    """
    Validate URL

    Args:
        url: URL string

    Returns:
        True if valid
    """
    pattern = r'^https?://[^\s/$.?#].[^\s]*$'
    return bool(re.fullmatch(pattern, url))

def validate_ip(ip: str) -> bool:
    """
    Validate IPv4 address

    Args:
        ip: IP string

    Returns:
        True if valid
    """
    pattern = r'^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$'
    return bool(re.fullmatch(pattern, ip))

def validate_date(date: str, format: str = 'YYYY-MM-DD') -> bool:
    """
    Validate date format

    Args:
        date: Date string
        format: Date format pattern

    Returns:
        True if valid
    """
    if format == 'YYYY-MM-DD':
        pattern = r'^\d{4}-\d{2}-\d{2}$'
        return bool(re.fullmatch(pattern, date))
    return False

def validate_password(password: str) -> dict:
    """
    Validate password strength

    Args:
        password: Password string

    Returns:
        Validation result dict
    """
    result = {
        'valid': True,
        'errors': [],
        'strength': 'weak'
    }

    if len(password) < 8:
        result['errors'].append('Password must be at least 8 characters')
        result['valid'] = False

    if not re.search(r'[a-z]', password):
        result['errors'].append('Password must contain lowercase letter')
        result['valid'] = False

    if not re.search(r'[A-Z]', password):
        result['errors'].append('Password must contain uppercase letter')
        result['valid'] = False

    if not re.search(r'\d', password):
        result['errors'].append('Password must contain digit')
        result['valid'] = False

    if not re.search(r'[!@#$%^&*(),.?":{}|<>]', password):
        result['errors'].append('Password must contain special character')
        result['valid'] = False

    # Calculate strength
    if result['valid']:
        if len(password) >= 12:
            result['strength'] = 'strong'
        else:
            result['strength'] = 'medium'

    return result

def validate_username(username: str) -> bool:
    """
    Validate username

    Args:
        username: Username string

    Returns:
        True if valid
    """
    pattern = r'^[a-zA-Z0-9_]{3,20}$'
    return bool(re.fullmatch(pattern, username))

def validate_hex_color(color: str) -> bool:
    """
    Validate hex color code

    Args:
        color: Color string

    Returns:
        True if valid
    """
    pattern = r'^#?([a-fA-F0-9]{6}|[a-fA-F0-9]{3})$'
    return bool(re.fullmatch(pattern, color))

def validate_postal_code(code: str, country: str = 'US') -> bool:
    """
    Validate postal code

    Args:
        code: Postal code string
        country: Country code

    Returns:
        True if valid
    """
    patterns = {
        'US': r'^\d{5}(-\d{4})?$',
        'UK': r'^[A-Z]{1,2}\d[A-Z\d]? ?\d[A-Z]{2}$',
        'CA': r'^[A-Z]\d[A-Z] ?\d[A-Z]\d$',
        'DE': r'^\d{5}$'
    }
    pattern = patterns.get(country, patterns['US'])
    return bool(re.fullmatch(pattern, code))

# 4. Extraction Operations
def extract_emails(text: str) -> List[str]:
    """
    Extract all email addresses

    Args:
        text: Input text

    Returns:
        List of emails
    """
    pattern = r'[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}'
    return re.findall(pattern, text)

def extract_urls(text: str) -> List[str]:
    """
    Extract all URLs

    Args:
        text: Input text

    Returns:
        List of URLs
    """
    pattern = r'https?://[^\s/$.?#][^\s]*'
    return re.findall(pattern, text)

def extract_phone_numbers(text: str) -> List[str]:
    """
    Extract all phone numbers

    Args:
        text: Input text

    Returns:
        List of phone numbers
    """
    pattern = r'\(?([0-9]{3})\)?[-. ]?([0-9]{3})[-. ]?([0-9]{4})'
    return re.findall(pattern, text)

def extract_numbers(text: str) -> List[str]:
    """
    Extract all numbers

    Args:
        text: Input text

    Returns:
        List of number strings
    """
    return re.findall(r'-?\d+\.?\d*', text)

def extract_hashtags(text: str) -> List[str]:
    """
    Extract all hashtags

    Args:
        text: Input text

    Returns:
        List of hashtags
    """
    return re.findall(r'#\w+', text)

def extract_mentions(text: str) -> List[str]:
    """
    Extract all @mentions

    Args:
        text: Input text

    Returns:
        List of mentions
    """
    return re.findall(r'@\w+', text)

def extract_dates(text: str) -> List[str]:
    """
    Extract dates in various formats

    Args:
        text: Input text

    Returns:
        List of date strings
    """
    patterns = [
        r'\d{4}-\d{2}-\d{2}',  # YYYY-MM-DD
        r'\d{2}/\d{2}/\d{4}',  # MM/DD/YYYY
        r'\d{1,2}\s+(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]*\s+\d{4}'
    ]
    dates = []
    for pattern in patterns:
        dates.extend(re.findall(pattern, text, re.IGNORECASE))
    return dates

def extract_html_tags(text: str) -> List[str]:
    """
    Extract HTML tags

    Args:
        text: Input text

    Returns:
        List of tags
    """
    return re.findall(r'<([a-zA-Z][a-zA-Z0-9]*)\b[^>]*>', text)

# 5. Replace Operations
def replace_pattern(text: str, pattern: str, replacement: str) -> str:
    """
    Replace all occurrences of pattern

    Args:
        text: Input text
        pattern: Regex pattern
        replacement: Replacement string

    Returns:
        Modified text
    """
    return re.sub(pattern, replacement, text)

def replace_first(text: str, pattern: str, replacement: str) -> str:
    """
    Replace first occurrence

    Args:
        text: Input text
        pattern: Regex pattern
        replacement: Replacement string

    Returns:
        Modified text
    """
    return re.sub(pattern, replacement, text, count=1)

def replace_nth(text: str, pattern: str, replacement: str, n: int) -> str:
    """
    Replace nth occurrence

    Args:
        text: Input text
        pattern: Regex pattern
        replacement: Replacement string
        n: Occurrence number (1-based)

    Returns:
        Modified text
    """
    count = 0
    def repl(match):
        nonlocal count
        count += 1
        if count == n:
            return replacement
        return match.group(0)
    return re.sub(pattern, repl, text)

def replace_with_func(text: str, pattern: str, func) -> str:
    """
    Replace using callback function

    Args:
        text: Input text
        pattern: Regex pattern
        func: Replacement function

    Returns:
        Modified text
    """
    return re.sub(pattern, func, text)

# 6. Text Processing
def remove_extra_spaces(text: str) -> str:
    """
    Remove extra whitespace

    Args:
        text: Input text

    Returns:
        Cleaned text
    """
    return ' '.join(text.split())

def remove_special_chars(text: str, keep: str = '') -> str:
    """
    Remove special characters

    Args:
        text: Input text
        keep: Characters to keep

    Returns:
        Cleaned text
    """
    pattern = f'[^a-zA-Z0-9\s{re.escape(keep)}]' if keep else '[^a-zA-Z0-9\s]'
    return re.sub(pattern, '', text)

def remove_html_tags(text: str) -> str:
    """
    Remove HTML tags

    Args:
        text: Input text

    Returns:
        Cleaned text
    """
    return re.sub(r'<[^>]+>', '', text)

def censor_words(text: str, words: List[str]) -> str:
    """
    Censor specific words

    Args:
        text: Input text
        words: Words to censor

    Returns:
        Censored text
    """
    for word in words:
        pattern = r'\b' + re.escape(word) + r'\b'
        text = re.sub(pattern, '*' * len(word), text, flags=re.IGNORECASE)
    return text

def highlight_text(text: str, pattern: str, marker: str = '**') -> str:
    """
    Highlight pattern matches

    Args:
        text: Input text
        pattern: Search pattern
        marker: Highlight markers

    Returns:
        Highlighted text
    """
    return re.sub(f'({pattern})', f'{marker}\1{marker}', text, flags=re.IGNORECASE)

# 7. Code Pattern Matching
def find_python_variables(text: str) -> List[str]:
    """
    Find Python variable names

    Args:
        text: Input text

    Returns:
        List of variable names
    """
    return re.findall(r'\b[a-zA-Z_][a-zA-Z0-9_]*\b', text)

def find_python_functions(text: str) -> List[str]:
    """
    Find Python function definitions

    Args:
        text: Input text

    Returns:
        List of function names
    """
    return re.findall(r'def\s+([a-zA-Z_][a-zA-Z0-9_]*)\s*\(', text)

def find_css_colors(text: str) -> List[str]:
    """
    Find CSS color codes

    Args:
        text: Input text

    Returns:
        List of color codes
    """
    return re.findall(r'#[a-fA-F0-9]{6}|#[a-fA-F0-9]{3}\b', text)

def find_json_keys(text: str) -> List[str]:
    """
    Find JSON keys

    Args:
        text: Input text

    Returns:
        List of keys
    """
    return re.findall(r'"([^"]+)":\s*', text)

# 8. Advanced Patterns
def find_palindromes(text: str) -> List[str]:
    """
    Find palindromes (case-insensitive)

    Args:
        text: Input text

    Returns:
        List of palindromes
    """
    words = re.findall(r'\b\w+\b', text)
    return [w for w in words if w.lower() == w[::-1].lower() and len(w) > 1]

def find_repeated_words(text: str) -> List[tuple]:
    """
    Find repeated words

    Args:
        text: Input text

    Returns:
        List of (word, count) tuples
    """
    words = re.findall(r'\b\w+\b', text.lower())
    from collections import Counter
    return [(word, count) for word, count in Counter(words).items() if count > 1]

def find_sentences_with_word(text: str, word: str) -> List[str]:
    """
    Find sentences containing word

    Args:
        text: Input text
        word: Word to search

    Returns:
        List of sentences
    """
    pattern = r'[^.!?]*\b' + re.escape(word) + r'\b[^.!?]*[.!?]'
    return re.findall(pattern, text, re.IGNORECASE)

# Usage Examples
def demonstrate_regex():
    print("=== Web Python Regular Expression Examples ===\n")

    # 1. Basic matching
    print("--- 1. Basic Pattern Matching ---")
    text = "The price is $123.45"
    pattern = r'\$\d+\.\d{2}'
    print(f"Text: {text}")
    print(f"Pattern: {pattern}")
    print(f"Find: {find_pattern(text, pattern)}")

    # 2. Validation
    print("\n--- 2. Validation ---")
    email = "[email protected]"
    print(f"Email: {email}")
    print(f"Valid: {validate_email(email)}")

    password = "MyPass123!"
    result = validate_password(password)
    print(f"\nPassword: {password}")
    print(f"Valid: {result['valid']}")
    print(f"Strength: {result['strength']}")
    if result['errors']:
        print(f"Errors: {result['errors']}")

    # 3. Extraction
    print("\n--- 3. Extraction ---")
    text = "Contact us at [email protected] or [email protected]"
    emails = extract_emails(text)
    print(f"Text: {text}")
    print(f"Emails: {emails}")

    text = "Call us at (555) 123-4567 or 555.987.6543"
    phones = extract_phone_numbers(text)
    print(f"\nText: {text}")
    print(f"Phone numbers: {phones}")

    # 4. Text processing
    print("\n--- 4. Text Processing ---")
    text = "This   has    extra     spaces"
    print(f"Original: '{text}'")
    print(f"Cleaned: '{remove_extra_spaces(text)}'")

    text = "Hello <b>world</b>! How are you?"
    print(f"\nOriginal: {text}")
    print(f"No HTML: {remove_html_tags(text)}")

    # 5. Replace
    print("\n--- 5. Replace Operations ---")
    text = "The color is red and red is nice"
    print(f"Original: {text}")
    print(f"Replace 'red' with 'blue': {replace_pattern(text, r'\bred\b', 'blue')}")

    # 6. Code patterns
    print("\n--- 6. Code Pattern Matching ---")
    code = "def calculate(x, y): return x + y"
    functions = find_python_functions(code)
    print(f"Code: {code}")
    print(f"Functions: {functions}")

    # 7. Advanced
    print("\n--- 7. Advanced Patterns ---")
    text = "level refers to the level of the radar"
    palindromes = find_palindromes(text)
    print(f"Text: {text}")
    print(f"Palindromes: {palindromes}")

    repeated = find_repeated_words(text)
    print(f"\nRepeated words: {repeated}")

    print("\n=== All Regular Expression Examples Completed ===")

# Export functions
export { find_pattern, find_all_patterns, match_pattern, full_match }
export { search_with_flags, find_iter, find_overlap, search_multiline }
export { validate_email, validate_phone, validate_url, validate_ip, validate_date }
export { validate_password, validate_username, validate_hex_color, validate_postal_code }
export { extract_emails, extract_urls, extract_phone_numbers, extract_numbers }
export { extract_hashtags, extract_mentions, extract_dates, extract_html_tags }
export { replace_pattern, replace_first, replace_nth, replace_with_func }
export { remove_extra_spaces, remove_special_chars, remove_html_tags }
export { censor_words, highlight_text }
export { find_python_variables, find_python_functions, find_css_colors, find_json_keys }
export { find_palindromes, find_repeated_words, find_sentences_with_word }
export { demonstrate_regex }

# Web Python String Replacement Examples
# Comprehensive string replacement operations and techniques

# 1. Basic Replacement
from typing import Dict, List, Callable, Any, Optional
import re

def replace_all(text: str, old: str, new: str) -> str:
    """
    Replace all occurrences

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string

    Returns:
        Modified string
    """
    return text.replace(old, new)

def replace_first(text: str, old: str, new: str) -> str:
    """
    Replace first occurrence

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string

    Returns:
        Modified string
    """
    index = text.find(old)
    if index != -1:
        return text[:index] + new + text[index + len(old):]
    return text

def replace_last(text: str, old: str, new: str) -> str:
    """
    Replace last occurrence

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string

    Returns:
        Modified string
    """
    index = text.rfind(old)
    if index != -1:
        return text[:index] + new + text[index + len(old):]
    return text

def replace_nth(text: str, old: str, new: str, n: int) -> str:
    """
    Replace nth occurrence (1-based)

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string
        n: Occurrence number

    Returns:
        Modified string
    """
    count = 0
    start = 0
    while True:
        index = text.find(old, start)
        if index == -1:
            break
        count += 1
        if count == n:
            return text[:index] + new + text[index + len(old):]
        start = index + len(old)
    return text

# 2. Count-Based Replacement
def replace_n_times(text: str, old: str, new: str, n: int) -> str:
    """
    Replace first n occurrences

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string
        n: Number of replacements

    Returns:
        Modified string
    """
    count = 0
    result = []
    start = 0

    while count < n:
        index = text.find(old, start)
        if index == -1:
            break
        result.append(text[start:index])
        result.append(new)
        start = index + len(old)
        count += 1

    result.append(text[start:])
    return ''.join(result)

def replace_if_count(text: str, old: str, new: str, condition: Callable[[int], bool]) -> str:
    """
    Replace based on occurrence count

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string
        condition: Function taking count, returns True to replace

    Returns:
        Modified string
    """
    count = 0
    result = []
    start = 0

    while True:
        index = text.find(old, start)
        if index == -1:
            break
        count += 1
        if condition(count):
            result.append(text[start:index])
            result.append(new)
        else:
            result.append(text[start:index + len(old)])
        start = index + len(old)

    result.append(text[start:])
    return ''.join(result)

# 3. Conditional Replacement
def replace_if_contains(text: str, old: str, new: str, condition: str) -> str:
    """
    Replace if text contains condition

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string
        condition: Condition string

    Returns:
        Modified string
    """
    if condition in text:
        return text.replace(old, new)
    return text

def replace_if_length(text: str, old: str, new: str, min_length: int = 0, max_length: int = float('inf')) -> str:
    """
    Replace based on text length

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string
        min_length: Minimum length
        max_length: Maximum length

    Returns:
        Modified string
    """
    if min_length <= len(text) <= max_length:
        return text.replace(old, new)
    return text

def replace_with_condition(text: str, old: str, new: str, condition: Callable[[str], bool]) -> str:
    """
    Replace based on custom condition

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string
        condition: Condition function

    Returns:
        Modified string
    """
    if condition(text):
        return text.replace(old, new)
    return text

# 4. Multiple Replacements
def replace_multiple(text: str, replacements: Dict[str, str]) -> str:
    """
    Replace multiple substrings

    Args:
        text: Input string
        replacements: Dictionary of {old: new}

    Returns:
        Modified string
    """
    for old, new in replacements.items():
        text = text.replace(old, new)
    return text

def replace_multiple_sequential(text: str, replacements: List[tuple]) -> str:
    """
    Replace sequentially (order matters)

    Args:
        text: Input string
        replacements: List of (old, new) tuples

    Returns:
        Modified string
    """
    for old, new in replacements:
        text = text.replace(old, new)
    return text

def replace_multiple_simultaneous(text: str, replacements: Dict[str, str]) -> str:
    """
    Replace multiple simultaneously (avoid conflicts)

    Args:
        text: Input string
        replacements: Dictionary of {old: new}

    Returns:
        Modified string
    """
    # Create pattern that matches any of the strings
    pattern = re.compile('|'.join(re.escape(key) for key in replacements.keys()))

    def repl(match):
        return replacements[match.group(0)]

    return pattern.sub(repl, text)

# 5. Pattern-Based Replacement
def replace_pattern(text: str, pattern: str, replacement: str) -> str:
    """
    Replace using regex pattern

    Args:
        text: Input string
        pattern: Regex pattern
        replacement: Replacement string

    Returns:
        Modified string
    """
    return re.sub(pattern, replacement, text)

def replace_pattern_func(text: str, pattern: str, func: Callable) -> str:
    """
    Replace using callback function

    Args:
        text: Input string
        pattern: Regex pattern
        func: Replacement function

    Returns:
        Modified string
    """
    return re.sub(pattern, func, text)

def replace_case_insensitive(text: str, old: str, new: str) -> str:
    """
    Replace ignoring case

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string

    Returns:
        Modified string
    """
    return re.sub(re.escape(old), new, text, flags=re.IGNORECASE)

def replace_word_boundaries(text: str, old: str, new: str) -> str:
    """
    Replace whole words only

    Args:
        text: Input string
        old: Word to replace
        new: Replacement word

    Returns:
        Modified string
    """
    pattern = r'\b' + re.escape(old) + r'\b'
    return re.sub(pattern, new, text)

# 6. Position-Based Replacement
def replace_at_position(text: str, start: int, end: int, replacement: str) -> str:
    """
    Replace text at position

    Args:
        text: Input string
        start: Start position
        end: End position
        replacement: Replacement string

    Returns:
        Modified string
    """
    return text[:start] + replacement + text[end:]

def replace_at_line(text: str, line_num: int, replacement: str) -> str:
    """
    Replace entire line

    Args:
        text: Input text (multiline)
        line_num: Line number (1-based)
        replacement: Replacement line

    Returns:
        Modified text
    """
    lines = text.split('\n')
    if 1 <= line_num <= len(lines):
        lines[line_num - 1] = replacement
    return '\n'.join(lines)

def replace_lines_matching(text: str, pattern: str, replacement: str) -> str:
    """
    Replace lines matching pattern

    Args:
        text: Input text (multiline)
        pattern: Line pattern
        replacement: Replacement line

    Returns:
        Modified text
    """
    lines = text.split('\n')
    for i, line in enumerate(lines):
        if re.search(pattern, line):
            lines[i] = replacement
    return '\n'.join(lines)

# 7. Template Replacement
def replace_placeholders(text: str, values: Dict[str, Any]) -> str:
    """
    Replace {placeholder} with values

    Args:
        text: Template string
        values: Dictionary of values

    Returns:
        Filled template
    """
    return text.format(**values)

def replace_placeholders_braced(text: str, values: Dict[str, Any]) -> str:
    """
    Replace ${placeholder} with values

    Args:
        text: Template string
        values: Dictionary of values

    Returns:
        Filled template
    """
    for key, value in values.items():
        text = text.replace(' + key + ', str(value))
    return text

def replace_percent_style(text: str, *args) -> str:
    """
    Replace %s style placeholders

    Args:
        text: Template string
        *args: Values

    Returns:
        Filled template
    """
    return text % args

# 8. Advanced Replacement
def replace_except(text: str, old: str, new: str, except_positions: List[int]) -> str:
    """
    Replace all except at positions

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string
        except_positions: List of positions to skip

    Returns:
        Modified string
    """
    result = []
    start = 0
    count = 0

    while True:
        index = text.find(old, start)
        if index == -1:
            break
        count += 1
        if count not in except_positions:
            result.append(text[start:index])
            result.append(new)
        else:
            result.append(text[start:index + len(old)])
        start = index + len(old)

    result.append(text[start:])
    return ''.join(result)

def replace_between(text: str, start_marker: str, end_marker: str, replacement: str) -> str:
    """
    Replace text between markers

    Args:
        text: Input string
        start_marker: Start marker
        end_marker: End marker
        replacement: Replacement string

    Returns:
        Modified string
    """
    pattern = re.escape(start_marker) + r'.*?' + re.escape(end_marker)
    return re.sub(pattern, start_marker + replacement + end_marker, text, flags=re.DOTALL)

def replace_with_fallback(text: str, old: str, new: str, fallback: str) -> str:
    """
    Replace with fallback if old not found

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string
        fallback: Fallback string

    Returns:
        Modified string
    """
    if old in text:
        return text.replace(old, new)
    return text + fallback

def replace_with_confirmation(text: str, old: str, new: str) -> tuple:
    """
    Replace with confirmation

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string

    Returns:
        (modified_text, count) tuple
    """
    count = text.count(old)
    modified = text.replace(old, new)
    return (modified, count)

# 9. Smart Replacement
def auto_capitalize_after_period(text: str) -> str:
    """
    Capitalize after periods

    Args:
        text: Input string

    Returns:
        Modified string
    """
    def repl(match):
        return match.group(1) + match.group(2).upper()

    return re.sub(r'([.!?]\s+)([a-z])', repl, text)

def fix_double_spaces(text: str) -> str:
    """
    Fix multiple spaces

    Args:
        text: Input string

    Returns:
        Modified string
    """
    return re.sub(r' +', ' ', text)

def fix_double_punctuation(text: str) -> str:
    """
    Fix repeated punctuation

    Args:
        text: Input string

    Returns:
        Modified string
    """
    return re.sub(r'([.!?])\1+', r'\1', text)

def normalize_whitespace(text: str) -> str:
    """
    Normalize all whitespace

    Args:
        text: Input string

    Returns:
        Modified string
    """
    return ' '.join(text.split())

def smart_quotes(text: str) -> str:
    """
    Convert straight quotes to smart quotes

    Args:
        text: Input string

    Returns:
        Modified string
    """
    # Opening quotes
    text = re.sub(r'"(\w)', r'"\1', text)
    # Closing quotes
    text = re.sub(r'(\w)"', r'\1"', text)
    return text

# 10. Batch Operations
def batch_replace(files_content: Dict[str, str], replacements: Dict[str, str]) -> Dict[str, str]:
    """
    Replace across multiple files

    Args:
        files_content: Dictionary of {filename: content}
        replacements: Dictionary of {old: new}

    Returns:
        Dictionary of modified contents
    """
    return {filename: replace_multiple(content, replacements)
            for filename, content in files_content.items()}

def replace_in_range(text: str, old: str, new: str, start: int, end: int) -> str:
    """
    Replace only within range

    Args:
        text: Input string
        old: Substring to replace
        new: Replacement string
        start: Range start
        end: Range end

    Returns:
        Modified string
    """
    before = text[:start]
    middle = text[start:end].replace(old, new)
    after = text[end:]
    return before + middle + after

# Usage Examples
def demonstrate_string_replace():
    print("=== Web Python String Replacement Examples ===\n")

    # 1. Basic replacement
    print("--- 1. Basic Replacement ---")
    text = "Hello World, World is beautiful"
    print(f"Original: {text}")
    print(f"Replace 'World' with 'Earth': {replace_all(text, 'World', 'Earth')}")
    print(f"Replace first: {replace_first(text, 'World', 'Earth')}")
    print(f"Replace last: {replace_last(text, 'World', 'Earth')}")
    print(f"Replace 2nd: {replace_nth(text, 'World', 'Earth', 2)}")

    # 2. Count-based
    print("\n--- 2. Count-Based Replacement ---")
    text = "cat cat cat dog cat"
    print(f"Original: {text}")
    print(f"Replace 2 cats: {replace_n_times(text, 'cat', 'CAT', 2)}")
    print(f"Replace if count > 3: {replace_if_count(text, 'cat', 'CAT', lambda c: c > 3)}")

    # 3. Multiple replacements
    print("\n--- 3. Multiple Replacements ---")
    text = "The quick brown fox jumps over the lazy dog"
    replacements = {'quick': 'slow', 'brown': 'white', 'lazy': 'active'}
    print(f"Original: {text}")
    print(f"After: {replace_multiple(text, replacements)}")

    # 4. Pattern-based
    print("\n--- 4. Pattern-Based Replacement ---")
    text = "Contact: [email protected] or [email protected]"
    print(f"Original: {text}")
    print(f"Mask emails: {replace_pattern(text, r'[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}', '***@***.***')}")

    # 5. Conditional
    print("\n--- 5. Conditional Replacement ---")
    text = "Hello World"
    print(f"Original: {text}")
    print(f"Replace if contains 'World': {replace_if_contains(text, 'World', 'Earth', 'World')}")

    # 6. Position-based
    print("\n--- 6. Position-Based Replacement ---")
    text = "Hello World Python"
    print(f"Original: {text}")
    print(f"Replace 6-11: {replace_at_position(text, 6, 11, 'Earth')}")

    # 7. Template
    print("\n--- 7. Template Replacement ---")
    template = "Hello {name}, welcome to {place}!"
    values = {'name': 'Alice', 'place': 'Wonderland'}
    print(f"Template: {template}")
    print(f"Filled: {replace_placeholders(template, values)}")

    # 8. Smart replacement
    print("\n--- 8. Smart Replacement ---")
    text = "hello  world.  this is   a test."
    print(f"Original: '{text}'")
    print(f"Normalize: '{normalize_whitespace(text)}'")
    print(f"Capitalize: '{auto_capitalize_after_period(text)}'")

    # 9. Advanced
    print("\n--- 9. Advanced Replacement ---")
    text = "Keep /* remove this */ and keep this"
    print(f"Original: {text}")
    print(f"Remove between markers: {replace_between(text, '/*', '*/', '')}")

    # 10. Word boundaries
    print("\n--- 10. Word Boundaries ---")
    text = "cat category concatenate"
    print(f"Original: {text}")
    print(f"Replace 'cat' whole word: {replace_word_boundaries(text, 'cat', 'DOG')}")

    print("\n=== All String Replacement Examples Completed ===")

# Export functions
export { replace_all, replace_first, replace_last, replace_nth }
export { replace_n_times, replace_if_count }
export { replace_if_contains, replace_if_length, replace_with_condition }
export { replace_multiple, replace_multiple_sequential, replace_multiple_simultaneous }
export { replace_pattern, replace_pattern_func, replace_case_insensitive, replace_word_boundaries }
export { replace_at_position, replace_at_line, replace_lines_matching }
export { replace_placeholders, replace_placeholders_braced, replace_percent_style }
export { replace_except, replace_between, replace_with_fallback, replace_with_confirmation }
export { auto_capitalize_after_period, fix_double_spaces, fix_double_punctuation }
export { normalize_whitespace, smart_quotes }
export { batch_replace, replace_in_range }
export { demonstrate_string_replace }