Regex to Match Characters in Words in iOS

Question

Hi i am Trying to Match Characters in Words Same as Email Search while Sending Emails. Where popover is shown. By Typing text, Text is Highlighted in Popover.

Anna Haro
anna-haro@mac.com
Hank M. Zakroff
hank-zakroff@mac.com

what is Tried is,

\bHa[\w-]* 

Expecting Match as,

Anna Ha ro

anna-haro@mac.com

Ha nk M. Zakroff

ha nk-zakroff@mac.com

Answer 1

Here are the way that you can highlight search string from whole string.

Step 1 : Add following method. that is created NSRegularExpression object for you.

- (NSRegularExpression *)regularExpressionWithString:(NSString *)string options:(NSDictionary *)options
{
    // Create a regular expression
    BOOL isCaseSensitive = [[options objectForKey:kRWSearchCaseSensitiveKey] boolValue];
    BOOL isWholeWords = [[options objectForKey:kRWSearchWholeWordsKey] boolValue];

    NSError *error = NULL;
    NSRegularExpressionOptions regexOptions = isCaseSensitive ? 0 : NSRegularExpressionCaseInsensitive;

    NSString *placeholder = isWholeWords ? @"\\b%@\\b" : @"%@";
    NSString *pattern = [NSString stringWithFormat:placeholder, string];

    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern options:regexOptions error:&error];
    if (error)
    {
        NSLog(@"Couldn't create regex with given string and options");
    }

    return regex;
}

Step 2 : Here are the code that highlight the find string from whole string.

// 4: Call the convenient method to create a regex for us with the options we have
    NSRegularExpression *regex = [self regularExpressionWithString:searchString options:options];

    // 5: Find matches
    NSArray *matches = [regex matchesInString:visibleText options:NSMatchingProgress range:visibleTextRange];

    // 6: Iterate through the matches and highlight them
    for (NSTextCheckingResult *match in matches)
    {
        NSRange matchRange = match.range;
        [visibleAttributedText addAttribute:NSBackgroundColorAttributeName value:[UIColor yellowColor] range:matchRange];
    }

Refer for more help

Edit :

Replace

 NSString *placeholder = @"\\b%@";

With

NSString *placeholder = isWholeWords ? @"\\b%@\\b" : @"%@";

Hope this help you.