Example for blog post at www.remarkablepixels.com on NSRegularExpressions

NSRegularExpressions Example iOS.m

- (NSString *)stripOutHttp:(NSString *)httpLine {
        // Setup an NSError object to catch any failures
	NSError *error = NULL;	
        // create the NSRegularExpression object and initialize it with a pattern
        // the pattern will match any http or https url, with option case insensitive
	NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"https?://([-\\w\\.]+)+(:\\d+)?(/([\\w/_\\.]*(\\?\\S+)?)?)?" options:NSRegularExpressionCaseInsensitive error:&error];
        // create an NSRange object using our regex object for the first match in the string httpline
	NSRange rangeOfFirstMatch = [regex rangeOfFirstMatchInString:httpLine options:0 range:NSMakeRange(0, [httpLine length])];
        // check that our NSRange object is not equal to range of NSNotFound
	if (!NSEqualRanges(rangeOfFirstMatch, NSMakeRange(NSNotFound, 0))) {
                // Since we know that we found a match, get the substring from the parent string by using our NSRange object
		NSString *substringForFirstMatch = [httpLine substringWithRange:rangeOfFirstMatch];
		NSLog(@"Extracted URL: %@",substringForFirstMatch);
                // return the matching string
		return substringForFirstMatch;
	}

	return NULL;
}