Question

I am making an iphone application. I have a scenario where i have a huge string, which has lot of data, and i would like to extract only email addresses from the string.

For example if the string is like

asdjasjkdh asdhajksdh jkashd [e-mail] asdha jksdh asjdhjak sdkajs [e-mail]

i should extract “[e-mail]” and “[e-mail]”

and i also want to extract only date, from the string

For example if the string is like

asdjasjkdh 01/01/2012 asdhajksdh jkas 12/11/2012 hd [e-mail] asdha jksdh asjdhjak sdkajs [e-mail]

i should extract “01/01/2012” and “12/11/2012”

A small code snipet, will be very helpful.

Thanks in advance

Answer 1

This will do what you want:

// regex string for emails (feel free to use a different one if you prefer)
NSString *regexString = @"([A-Za-z0-9_\\-\\.\\+])+\\@([A-Za-z0-9_\\-\\.])+\\.([A-Za-z]+)";

// experimental search string containing emails
NSString *searchString = @"asdjasjkdh 01/01/2012 asdhajksdh jkas 12/11/2012 hd [e-mail] asdha jksdh asjdhjak sdkajs [e-mail]";

// track regex error
NSError *error = NULL;

// create regular expression
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:regexString options:0 error:&error];

// make sure there is no error
if (!error) {

    // get all matches for regex
    NSArray *matches = [regex matchesInString:searchString options:0 range:NSMakeRange(0, searchString.length)];

    // loop through regex matches
    for (NSTextCheckingResult *match in matches) {

        // get the current text
        NSString *matchText = [searchString substringWithRange:match.range];

        NSLog(@"Extracted: %@", matchText);

    }

}

Using your sample string above:

asdjasjkdh 01/01/2012 asdhajksdh jkas 12/11/2012 hd [e-mail] asdha jksdh asjdhjak sdkajs [e-mail]

The output is:

Extracted: [e-mail]
Extracted: [e-mail]

To use the code, just set searchString to the string you want to search. Instead of the NSLog() methods, you’ll probably want to do something with the extracted strings matchText. Feel free to use a different regex string to extract emails, just replace the value of regexString in the code.