Question

I have to check the third character in the string. I’m trying to do that with NSPredicate. I thought the regular expression should be ..3* so it will find every string with third character 3. But its not working and I did try some others approaches without success :(. Can someone help me ?

simple code to checking

- (IBAction)btnCheckPerformClick:(id)sender {
_chkOk.state = NO;
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF like[c] %@", _txtRegExpression.stringValue];
NSLog(@"%@", predicate);
if([predicate evaluateWithObject:_txtCheckingText.stringValue])
    _chkOk.state = YES;
}

thanks

Answer 1

The LIKE operator in the predicate format language only understands simple wildcards (? and *). You need to use MATCHES if you want to use a regular expression.

See the Predicate Programming Guide (String Comparisons) for more details.

Alternatively, use NSRegularExpression.