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Regex Replace Previewer

Preview regex replacements in real-time with detailed diff highlights and statistics

Details

What this tool helps you do

Features:

Real-time preview of text replacements
Support for capture groups ($1, $2, ${name})
Special patterns: $& (full match), $` (prefix), $' (suffix), $$ (literal $)
Diff highlights showing changes
Detailed statistics on replacements

Example Usage:
Pattern: \b(\d{4})-(\d{2})-(\d{2})\b
Replacement: $2/$3/$1
Input: "Dates: 2024-01-15 and 2024-02-20"
Output: "Dates: 01/15/2024 and 02/20/2024"

Execution

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Result

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Run the tool to preview files, text, structured data, or streamed output here.

Result

Ready for a run

Run the tool to preview files, text, structured data, or streamed output here.

Samples

Examples that match this tool

Regex24

Diff17

Tool usage guide

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Category: Development
Input types: textarea, text, select
Output type: json
Sample coverage: 4
API ready: Yes

Overview

The Regex Replace Previewer is a development tool that lets you test regular expression substitutions in real-time. It provides immediate visual feedback with diff highlights and detailed statistics, ensuring your patterns work as expected before deployment.

When to use

When developing or debugging regex patterns for text processing tasks.

To visually confirm how replacements will alter your text with highlighted differences.

For analyzing the impact of regex operations through match and replacement counts.

How it works

1Input your original text into the designated textarea.
2Define the regex pattern and replacement template, utilizing capture groups like $1 or special patterns such as $&.
3Set optional regex flags (e.g., g for global) and select a preview mode (side-by-side, inline-diff, or result-only).
4The tool instantly displays the modified text with changes highlighted and provides statistics on the replacements made.

Use cases

Reformatting date strings in log files to a different standard.
Cleaning and standardizing phone numbers or email addresses in datasets.
Extracting specific data patterns from unstructured text for analysis.

Examples

1. Convert Date Formats

Software Developer

Background

Working with server logs that contain dates in ISO format (YYYY-MM-DD).

Problem

Need to change dates to US format (MM/DD/YYYY) for a compliance report.

How to use

Enter the log text, set pattern to `\b(\d{4})-(\d{2})-(\d{2})\b`, and replacement to `$2/$3/$1`.

Outcome

Dates are converted, and the diff view shows all changes clearly.

2. Standardize Phone Numbers

Background

Has a CSV file with phone numbers in various formats like (123) 456-7890 and 123-456-7890.

Problem

Inconsistent formats prevent accurate data merging and analysis.

How to use

Use a regex pattern to match different formats, e.g., `(\d{3})[^\d]*(\d{3})[^\d]*(\d{4})`, and replacement `$1-$2-$3`.

Outcome

All phone numbers are standardized to 123-456-7890 format, with statistics showing the number of replacements.

FAQ

What regex flags can I use?

Common flags like g (global), i (case-insensitive), and m (multiline) are supported.

How do I use capture groups in replacements?

Use $1, $2, etc., to refer to captured groups in the replacement template.

What are the special replacement patterns?

Special patterns include $& for the full match, $` for the prefix, $' for the suffix, and $$ for a literal dollar sign.

Can I see a diff of the changes?

Yes, the tool highlights additions, deletions, and modifications in the preview.

Does it provide statistics on replacements?

Yes, it shows the number of matches found and replacements made.

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Regex Replace Previewer

What this tool helps you do

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Examples that match this tool

Continue with connected tools and hubs

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Convert Date Formats

2. Standardize Phone Numbers

FAQ

Regex Replace Samples

Regex Pattern Alternatives

Regex Named Capture Groups

Common Regex Patterns

Text File Replacer

Text File Searcher

Regex Debugger

Regex Railroad Diagram Visualizer

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