MSLibrary. SIMPLE: remove unnecessary characters from a string using regular expressions for iOS and not only ...

In addition to large and detailed materials, the developers of the MSLibrary for iOS library decided to start a series of very compact articles on how to just implement a particular function. No theory, just practice ...

So, we remove unnecessary characters from a string using regular expressions using a simple function:

NSString *yourFuncionName(NSString *string) { NSString *regExString = @"yourRegularExpression"; NSRegularExpression *_regEx = [NSRegularExpression regularExpressionWithPattern:regExString options:NSRegularExpressionCaseInsensitive error:nil]; return [_regEx stringByReplacingMatchesInString:string options:0 range:NSMakeRange(0, [string length]) withTemplate:@""]; } 

That's all, it remains to find the appropriate regular expression that solves the problems you set.
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Some useful regular expressions:

     \\ s - removes all spaces.
     [-: _ \\.] - removes all characters in square brackets
     [: ^ digit:] - leaves only numbers
     [: ^ alpha:] - leaves only letters
     [: ^ alnum:] - leaves only letters and numbers
     [: ^ word:] - leaves only letters, numbers and underscores

Important: do not forget to screen all meta-characters with "\\" in regular expressions

For those who only master the skills, we will give an example of a code that leaves only numbers in a line:

 NSString *function_OnlyDigitsInString(NSString *string) { NSString *regExString = @"[:^digit:]"; NSRegularExpression *_regEx = [NSRegularExpression regularExpressionWithPattern:regExString options:NSRegularExpressionCaseInsensitive error:nil]; return [_regEx stringByReplacingMatchesInString:string options:0 range:NSMakeRange(0, [string length]) withTemplate:@""]; } 

As you can see, the issue is solved in just a few simple lines of code, and when using the MSLibrary for iOS library, in one line.

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We hope that the material was useful to you, the MSLibrary for iOS team

Other articles:
Capture and verify phone numbers using regular expressions, for iOS and not only ... Part 1
Capturing and verifying phone numbers using regular expressions, for iOS and not only ... Part 2
Implementing multiple selection of conditions using bitmasks, for iOS and not only ...
Creating and compiling cross-platform (universal) libraries in Xcode