Whats the quickest way to do lots of NSRange calls in a very long NSString on iOS?

Question

I have a VERY long NSString . It contains about 100 strings I need to pull out of it, all randomly scattered throughout. They are all commonly are between imgurl= and & .

I could use NSRange and just loop through pulling out each string, but I'm wondering if there is a quicker was to pick out everything in a simple API call? Maybe something I am missing here?

Looking for the quickest way to do this. Thanks!

Answer 1

Using NSString methods componentsSeparatedByString and componentsSeparatedByCharactersInSet :

NSString *longString = some really long string;
NSArray *longStringComponents = [longString componentsSeparatedByString:@"imgurl="];
for (NSString *string in longStringComponents){
    NSString *imgURLString = [[string componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"&"]] firstObject];
    // do something with imgURLString...
}

Answer 2

If you feel adventurous then you can use regular expression. Since you said that the string you are looking is between imgurl and & , I assumed its a url and made the sample code to do the same.

    NSString *str = @"http://www.example.com/image?imgurl=my_image_url1&imgurl=myimageurl2&somerandom=blah&imgurl=myurl3&someother=lol";

    NSError *error = NULL;
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(?:imageurl=)(.*?)(?:&|\\r)"
                                                                           options:NSRegularExpressionCaseInsensitive
                                                                             error:&error];
    //should do error checking here...


    NSArray *matches = [regex matchesInString:str
                                      options:0
                                        range:NSMakeRange(0, [str length])];
    for (NSTextCheckingResult *match in matches)
    {
        //[match rangeAtIndex:0] <- gives u the whole string matched.
        //[match rangeAtIndex:1] <- gives u the first group you really care about.
        NSLog(@"%@", [str substringWithRange:[match rangeAtIndex:1]]);
    }

If I were you, I will still go with @bobnoble method because its easier and simpler compared to regex. You will have to do more error checking using this method.