regex

// Without this library
NSString* string = @"I have 2 dogs.";
NSRegularExpression *regex = [NSRegularExpression regular ExpressionWithPattern:@"\\d+" options:NSRegularExpressionCaseInsensitive error:&error];
NSTextCheckingResult *match = [regex firstMatchInString:string options:0 range:NSMakeRange(0, [string length])];
BOOL isMatch = match != nil;

// With this library
BOOL isMatch = [@"I have 2 dogs." isMatch:RX(@"\\d+")];