Using a MatchEvaluator methodīut if we want even more control over how the value is replaced? We can use a MatchEvaluator parameter for this - it's basically just a reference (delegate) to a method which will be called each time a replacement is to be made, allowing you to modify the replacement value before it's used. String cleanString = regex.Replace(testString, "[$ notation. You can of course do the exact same thing when using named capture groups (discussed in the previous article), like this: string testString = "Hello, world" With that in place, our output will now look like this: Hello, world Named Capture Groups In the Replace() method I reference this using the special notation $1, which basically just means capture group number 1. I actually just changed two minor details: I added a set of parentheses to the regex, to create a capture group, essentially capturing the value between the angle brackets into the first capture group. This is where Regular Expressions really show their power, because it's actually very easy, as illustrated by this slightly rewritten version of our previous example: string testString = "Hello, world" by replacing the angle brackets () with square brackets (). ![]() Replacing with Captured Valuesīut let's say that you don't actually want to remove them, but instead, you want to transform the tags into something that will not be interpreted by a browser, e.g. We match anything that is surrounded by a set of angle brackets () and then we use the Replace() method to replace each occurrence with an empty string, basically removing the HTML tags from the test string. This example displays a very simplified approach to removing HTML tags from a string. String cleanString = regex.Replace(testString, "") We'll use the Replace() method found on the Regex class: string testString = "Hello, world" With that in place, let's try working with Regular Expression based string replacement. Does it sound complicated? Don't worry, we'll start with a simple example and then slowly work toward more advanced use cases.Īs in the previous article, all examples assume that you have imported the RegularExpressions namespace, like this: using When using Regular Expressions, you can use the power of regex searches and even use captured groups as part of the replace string. The String class already has a Replace() method, but this is only good for doing simple searches. Regular Expressions are great for that, but another use case is when you want to carry out search/replace operations, where you want to look for a specific pattern and replace it with something else. We have already discussed the Regex class and how to use it when we want to search through a string in a previous article. Regular Expressions (Regex): Search/Replace with the Regex Class However, when you specifically search for metacharacters such as. Keep in mind that if you copy ( Ctrl C) the string first and then paste ( Ctrl V) it in the search field, the regex symbols will not be taken into account. When you search for a text string that contains special regex symbols, GoLand automatically escapes them with backlash \ in the search field. If you want to check the syntax of regular expressions, hover over and click the Show expressions help link. If you need to search and replace in more than one file, press Ctrl Shift R.Įnter a search string in the top field and a replace string in the bottom field.Ĭlick to enable regular expressions. Press Ctrl R to open the search and replace pane. ![]() ![]() Once you learn the regex syntax, you can use it for almost any language. They can help you in pattern matching, parsing, filtering of results, and so on. When you want to search and replace specific patterns of text, use regular expressions. Find and replace text using regular expressions
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