Regular Expressions, or 'Regex,' is a powerful way to search for text patterns rather than just specific words. It acts like a super-powered 'Find' tool for your computer.

The Super Search Language

The simplest way to use regex is to type out the exact word you want to find. This works just like searching for a name in a digital document.

Matching Exact Words

A single period acts as a 'wildcard' that can represent any single letter, number, or symbol. It is useful when you know a word's length but not every character.

The Universal Wildcard

You can use square brackets to tell the computer to look for any one character from a specific list. For example, you could search for several different vowels at the same time.

Creating Custom Lists

You can instruct the search tool to ignore certain letters or symbols by using a special 'not' command. This helps you filter out text you definitely do not want to see.

Excluding Specific Characters

Instead of listing every number, you can use a shortcut to find any single digit from zero to nine. This makes it easy to spot things like phone numbers or dates.

Fast Number Shortcuts

A simple code can represent any letter or number. This is a fast way to find whole words or usernames without having to type out the entire alphabet.

Quick Word Shortcuts

There is a specific shortcut to find spaces, tabs, and line breaks. This is helpful for cleaning up messy formatting in a long document.

Finding Hidden Spaces

You can mark a character as optional, meaning the search will work whether that character is there or not. This is perfect for words with different spellings, like 'color' and 'colour.'

Making Parts Optional

A special symbol tells the computer to find a character that appears at least once or many times in a row. It is great for finding long strings of the same letter.

One or More Repeats

This allows you to find a pattern that might appear many times or not at all. It provides flexibility when you are not sure how much text to expect.

Zero or More Repeats

You can specify the exact number of times a character should repeat, such as exactly five digits. This is the best way to find codes like zip codes or serial numbers.

Setting Exact Counts

You can force a search to only look at the very beginning of a sentence or line. This prevents the tool from picking up matches buried in the middle of other words.

Finding the Start

You can specify that a pattern must appear at the very end of a line. This is useful for finding specific file types or specific sentence endings.

Finding the End

You can use a vertical bar symbol to search for 'this' or 'that.' It allows you to find multiple different terms simultaneously with one search.

Choosing Between Options

Parentheses allow you to bundle parts of your search together as a single unit. This lets you apply rules, like repeats or choices, to whole phrases instead of just one letter.

Grouping Related Parts

To find symbols that regex normally uses for rules, like a period or question mark, you must use a 'backslash.' This tells the computer to treat the symbol as normal text.

Regular Expressions (Regex) Concepts