NSNumberFormatter 千分符

　　NSNumberFormatter *formatter=[[NSNumberFormatter alloc]init];
    [formatter setGroupingSeparator:@","];
    [formatter setGroupingSize:3];
    [formatter setUsesGroupingSeparator:YES];
    NSNumber *num= [NSNumber numberWithInt:144343];
    NSString *str = [formatter stringFromNumber:num];

　　结果：144,343