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A regular expression (regex) is a powerful sequence of characters that defines a search pattern. Developers and data professionals use regex to match, search, and replace text based on specific patterns. Whether you're validating email addresses, extracting URLs, or finding specific words in a document, regex provides the flexibility to handle complex text processing tasks.
SEO professionals regularly use regex in Google Search Console to filter and analyze data. For example, you can use regex to match specific URL patterns, extract subdomains, or identify page categories. Understanding basic regex syntax helps you get more value from tools like Google Analytics and Search Console.
^/blog/ - Match URLs starting with /blog/\.pdf$ - Match URLs ending with .pdf(jpg|png|gif) - Match image file typestel:\d+ - Match phone numbersFlags modify how the regex engine interprets your pattern. The global flag (g) finds all matches rather than stopping at the first. Case insensitive (i) makes the pattern match regardless of capital letters. Multiline (m) changes how ^ and $ work—they now match the start and end of each line rather than just the string.
Start simple and build incrementally. Test each part of your pattern as you go. Use character classes like \d for digits or \w for word characters instead of listing every possible option. Remember that regex is greedy by default—use ? after * or + to make it non-greedy when needed.