I work with NSURL from time to time and invariably need a chart to remind me what the class provides in the form of helpers. I tend to write something like the following to refresh my memory.

- (void)displayURLInfo:(NSURL *)url {
    NSLog(@"absoluteString: %@", url.absoluteString);
    NSLog(@"absoluteURL: %@", url.absoluteURL);
    NSLog(@"baseURL: %@", url.baseURL);
    NSLog(@"fileSystemRepresentation: %s", url.fileSystemRepresentation);
    NSLog(@"fragment: %@", url.fragment);
    NSLog(@"host: %@", url.host);
    NSLog(@"lastPathComponent: %@", url.lastPathComponent);
    NSLog(@"parameterString: %@", url.parameterString);
    NSLog(@"password: %@", url.password);
    NSLog(@"path: %@", url.path);
    NSLog(@"pathComponents: %@", url.pathComponents);
    NSLog(@"pathExtension: %@", url.pathExtension);
    NSLog(@"port: %@", url.port);
    NSLog(@"query: %@", url.query);
    NSLog(@"relativePath: %@", url.relativePath);
    NSLog(@"relativeString: %@", url.relativeString);
    NSLog(@"resourceSpecifier: %@", url.resourceSpecifier);
    NSLog(@"scheme: %@", url.scheme);
    NSLog(@"standardizedURL: %@", url.standardizedURL);
    NSLog(@"user: %@", url.user);
}

Here’s a couple of handy charts to help you decide which property to use.

File URLs (nulls removed)

Internet URLs (nulls removed)

Helpful? Anyone? Anyone?