Remove all non-numeric characters from an NSString, keeping spaces

Question

I am trying to remove all of the non-numeric characters from an NSString, but I also need to keep the spaces. Here is what I have been using.

NS         


        

Answer 1

In brief, you can use NSCharacterSet to examine only those chars that are interesting to you and ignore the rest.

- (void) stripper {

    NSString *inString = @"A1 B2 C3 D4";
    NSString *outString = @"";

    for (int i = 0; i < inString.length; i++) {

        if ([[NSCharacterSet whitespaceCharacterSet] characterIsMember:[inString characterAtIndex:i]] || [[NSCharacterSet decimalDigitCharacterSet] characterIsMember:[inString characterAtIndex:i]]) {

            outString = [outString stringByAppendingString:[NSString stringWithFormat:@"%c",[inString characterAtIndex:i]]];
        }
    }
}