Validating a file with regular expressions
For example, with regex you can easily check a user’s input for common misspellings of a particular word (e.g. This guide provides a regex cheatsheet that you can use as a reference when creating regex expressions.
We will also go over a couple of popular regex examples and mention a few tools you can use to validate / create your regex expressions.
To match a particular email address with regex we need to utilize various tokens.
The following regex snippet will match a commonly formatted email address.
For example if you want to make sure that the person filling a form submits exactly the text you require, you can use a regular expression to enforce a certain pattern of the input or to validate the data.
As an example, let's say that you want to ask for a UK National Insurance Number (NIN).
It has a pattern of 2 characters, followed by 6 digits, follow by another character.
According to my understanding, below will be the code to perform the above: In explanation: "matches" is a method on String.Consult the following regex cheatsheet to get a quick overview of what each regex token does within an expression.With the regex cheatsheet above, you can dissect and verify what each token within a regex expression actually does.Therefore, with the above regex expression for finding phone numbers, it would identify a number in the format of 123-123-1234, 123.123.1234, or 1231231234.There are a few tools available to users who want to verify and test their regex syntax.