![]() You may notice that this actually overrides the matching of the. Regex. (dot) metacharacter, and can match any single character (letter, digit, whitespace, everything). Regex.exec('string') - Returns null or array containing the match / - Escape a forward slash (char code 47) Z? - Match 0 or 1 of the preceding character Z+ - Match 1 or more of the preceding character To match a character having special meaning in regex, you need to use a escape sequence prefix with a backslash ( ). Match any character that is not in the set. Z* - Match 0 or more of the preceding character Roll-over elements below to highlight in the Expression above. Moving on we have - Match preceding token longer than 2 characters w+ is a word character set with a quantifier (+) that matches one or more word characters. Can you guess what will do? That’s right, it will select every letter from a to z including every digit from 0 to 9. Multiple characters can be stacked by simply writing them one after another. To include uppercase as well you need to say. Note that this will only select lowercase letters. For example to do the same, you can alternatively use. To select a set of characters you can use brackets. The regex language takes some time to get use to, but once you have a regex, using it in Javascript is easy. Ends with any number of alphanumeric or underscore characters after the x. Character classes - also called “Character Sets” - lets you tell the regex engine to match either a single or a set of characters. If there are substrings that match overlapping pieces of text, only the index. Looking to improve your skills? Check out our interactive course to master JavaScript from start to finish. So let’s examine what we have between //g and what do they actually mean. ![]() ![]() You see, everything that goes between the slashes will get picked up by regex. In case you want to select all occurrences then you need the global flag as well, making it /javascript/gi. ![]() Say you want to select both javascript and JavaScript in a piece of text. Otherwise, only the first occurrence will be matched. In order to select every occurrence, you have to set the global flag. Say you have a paragraph in which the digits appear more than once. They mean global and case insensitive respectively. The two most common one you are going to come across are g and i or the combination of both: gi. We can also have flags after the closing slash. Every regex pattern is denoted by two /, the pattern itself goes between them. Any individual character between the brackets will match, and you can also. Now let’s break it down, starting from the basics. A regex literal is just what we have been using, /slashes with rules inside/. Copied to clipboard! Copy Above example represented with a diagramīefore starting, I would like to advise you to follow along by copy-pasting the examples into RegExr and play around with the “Text” field. ![]()
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