nsrangeexample.m

#import <Foundation/Foundation.h>




@interface MyClass : NSObject
- (NSString *)actualPhotoPath:(NSDictionary *)input;
@end

@implementation MyClass

- (NSString *)actualPhotoPath:(NSDictionary *)input
{
    NSRange r1 = [[input objectForKey:@"pic"] rangeOfString:[input objectForKey:@"username"]];
    NSRange r2 = [[input objectForKey:@"pic"] rangeOfString:@".png"];
    
    if(r1.location != NSNotFound && r2.location != NSNotFound){
        NSRange rSub = NSMakeRange(r1.location + r1.length, r2.location - r1.location - r1.length);
        
        NSString *sub = [[input objectForKey:@"pic"] substringWithRange:rSub];
        NSString *actual = [NSString stringWithFormat:@"%@%@.png",[input objectForKey:@"username"],sub];
        NSLog(@"%@",actual);
        return actual;
    }
    
    // if the code reaches this block, one of the ranges didn't work.
    // do what ever must be done in that case here
    return nil;
}

@end



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

    @autoreleasepool {
        NSDictionary *dict = @{@"username": @"vikingosegundo", @"pic": @"vikingosegundo123.png"};
        
        MyClass *obj = [[MyClass alloc] init];
        
        NSString *file = [obj actualPhotoPath:dict];
        
    }
    return 0;
}