Question

I’m trying to find and replace any occurrence of [URL] in an NSString. This is my approach:

NSString *test = @"Test [URL] 123";
test = [test stringByReplacingOccurrencesOfString:@"[URL]"
                                       withString:@"HERE"
                                          options:NSRegularExpressionSearch
                                            range:NSMakeRange(0, test.length)];

The result of this is Test [HEREHEREHERE] 123.
I guess it’s because [URL] means any of those 3 characters, so all 3 characters will be replaced with HERE one after another.

However I also tried \[URL\] with the same result.

So, how do I actually search for the characters [ and ]?

Answer 1

You are absolutely right about diagnosing your problem: the square brackets are meta-characters in the regular expression language, so they get interpreted by the regex engine.

You need to double-escape your slashes, because they are special characters in both Objective-C and regexp language: @"\\[URL\\]"