Always run through the regular expressions search that you’ve created 4-5 times just in the find mode in the text editor to make sure it isn’t selecting anything that you don’t intend it to, before you replacing that found text with something else.That way you can always go back to the original if you’ve gotten rid of a too broad selection and need to try again. Always do this editing and playing around with different possibilities in a new version of your file and make sure that a version exists of the raw text file you're trying to clean up.The latter is what I’ll be using it for in the tutorials below, to show you how to use regex to find certain blocks of text that you want to cut from your document to make it easier to analyze, and then cut those sections as a batch rather than individually.Ī word of caution though - it is a pretty easy mistake to write a regex that applies to text you don’t actually want cut and not even know you’ve gotten rid of it until a much later step of the process. Regular Expressions are a powerful method to find broad amounts of text that match a given pattern and so are often used for data validation or for find-and-replace operations in a document. Or as it can be written out as a regex search - \d 3 digits followed by a dash, 3 more digits, followed by another dash and then finally 4 digits. With regular expressions, you can take a look at the kinds of phone numbers that you want to find like say, 21 and take note of the pattern within it. With those methods, you’d have to go through all manner of three digit number configurations to try and make sure you’d tracked down every phone number by searching from 001 to 999 and checking each result to make sure that you didn’t just find an instance of the person writing down a 3 digit number for another reason. Without that text clue at the front, you’d have a difficult time searching for phone numbers using typical search methods. Regex lets you cast a wider net.įor instance, let's say you had a transcription of someone’s diary and you wanted to find every mention of a phone number. However while the author always wrote out the full phone number, they seldom mentioned the word phone or call beforehand. With ordinary search methods, you have to be more exact with what you are searching for because you can only ask it to look for an exact series of characters, rather than a pattern. Patterns of certain kinds of characters, for instance you can look only for email addresses that fit the pattern of needing to know all the names you’d be looking for, all the school names or even all the numbers.Specific kinds of characters like capital letters, lowercase letters, numbers, numbers within a certain range.Specific characters only within a word or only at the end of a word – searching for *cat will find you bearcat but not category, cat* will find you category but not bearcat.Specific terms like a regular search – cat finds cat.This means that by using combinations of characters, wildcards and other symbols it can be used to look for the following and more: Regular expressions (also called regex) is a method supported by many programming languages and text editors that allows you to not only search for certain exact keywords or phrases but also for certain patterns of characters within a text. ![]() Information Visualization
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