Objective-C: Find numbers in string

Question

I have a string that contains words as well as a number. How can I extract that number from the string?

NSString *str = @\"This is my string. #1234\";
         


        

Answer 1

Self contained solution:

+ (NSString *)extractNumberFromText:(NSString *)text
{
  NSCharacterSet *nonDigitCharacterSet = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
  return [[text componentsSeparatedByCharactersInSet:nonDigitCharacterSet] componentsJoinedByString:@""];
}

Handles the following cases:

• @"1234" → @"1234"
• @"001234" → @"001234"
• @"leading text get removed 001234" → @"001234"
• @"001234 trailing text gets removed" → @"001234"
• @"a0b0c1d2e3f4" → @"001234"

Hope this helps!