I have this NSString:
@"aa.bb.cc.png"
I want to insert myString right before the .png to make
@"aa.bb.ccSTUFF.png"
Is there a better way to do this than to reverse iterate until '.' is found, then split at location, then add component1 + stuff + extension together?
Thanks
Try this:
NSString *path = [originalPath stringByDeletingPathExtension];
path = [path stringByAppendingString:myString];
path = [path stringByAppendingPathExtension:[originalPath pathExtension]];
You can use regular expression for that:
NSError *error = NULL;
NSRegularExpression *regex = [NSRegularExpression
regularExpressionWithPattern:@"[.]([^.]*)$"
options:NSRegularExpressionCaseInsensitive
error:&error];
NSString *res = [regex stringByReplacingMatchesInString:str
options:0
range:NSMakeRange(0, [str length])
withTemplate:@"STUFF.$1"];
The idea behind the regex is to match the last dot and the extension, and then replace with the additional string of your choice ($1 in the replacement template means the content of the first capturing group, which corresponds to the extension).
stringByReplacingMatchesInString method by themselves would probably be less expensive than two appends, because each call does not create a throw-away object in between the two invocations. In the end, the difference in performance would likely not matter at all, so it's going to be a matter of personal preferences.