Question

I need the regex formula for
ex “17% off etc etc”
or “2% off etc etc etc”
so if the string starts with a one or 2 digit number followed by the percent sign, space, and the word ‘off’

I tried

NSPredicate* test = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", @"^[0-9]{1,2}% off"];
if ( [test evaluateWithObject:candidate] )
{
.... etc..

but no luck.

I appreciate any insight.

Answer 1

With this command line example app it works just fine.

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[])
{

    @autoreleasepool {

        NSArray *lines = @[ @"17% off etc.", @"2% off", @"off by 12%" ];
        NSPredicate* test = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", @"^[0-9]{1,2}% off.*"];

        [lines enumerateObjectsUsingBlock:^(NSString  *candidate, NSUInteger idx, BOOL *stop) {
            if ( [test evaluateWithObject:candidate] ){
                NSLog(@":)");
            } else{
                NSLog(@":(");
            }
        }];


    }
    return 0;
}

output:

2012-08-08 15:46:16.213 regextest[1305:303] :)
2012-08-08 15:46:16.215 regextest[1305:303] :)
2012-08-08 15:46:16.215 regextest[1305:303] :(

---

If the line contains more chars, it should look like

NSPredicate* test = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", @"^[0-9]{1,2}% off.*"];

the .* indicates, that any number of any char might be present.