Question

I need to get url string from NSString. I do the following:

   NSString * str = [NSString stringWithString:@"[e-mail]"];

    NSString * eStr = [str stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

    NSLog(@"%@",eStr);

The result is [e-mail]. But I need i%40gmail.com. replacing NSUTF8StringEncoding with NSASCIIStringEncoding doesn’t help.

Answer 1

You’re using the wrong method. This does the opposite, translating percent
escapes to their characters. You probably want to use
stringByAddingPercentEscapesUsingEncoding:.

NSString *str  = @"[e-mail]";
NSString *eStr =
    [str stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

---

Apart from that, looks like the @ character is not escaped by default. Then,
as the documentation for the above method points out, you’ll need to use
CoreFoundation to achieve what you want.

NSString *str  = @"[e-mail]";

CFStringRef eStr = CFURLCreateStringByAddingPercentEscapes(
    kCFAllocatorDefault,
    (CFStringRef)str,
    NULL,
    (CFStringRef)@"@",
    kCFStringEncodingUTF8
);

NSLog(@"%@", eStr);

CFRelease(eStr);

Please check the documentation to know more about the function used and
how to make it fit your needs.