This is dependent on the programming language and on its string handling options. For example, in Java strings, if you need a literal backslash in a string, you need to double it. So the regex \n must be written as “\\n”. If you plan to match a backslash using a regex, then you need to escape it twice … Read more
Use the grepl function like so: Use ?grepl to find out more.
A semicolon is reserved and should only for its special purpose (which depends on the scheme). Section 2.2: Many URL schemes reserve certain characters for a special meaning: their appearance in the scheme-specific part of the URL has a designated semantics. If the character corresponding to an octet is reserved in a scheme, the octet must be … Read more
First off, your format validator is obviously only appropriate for NANP (country code +1) numbers. Will your application be used by someone with a phone number from outside North America? If so, you don’t want to prevent those people from entering a perfectly valid [international] number. Secondly, your validation is incorrect. NANP numbers take the form NXX NXX … Read more
Since phone numbers must conform to a pattern, you can use regular expressions to match the entered phone number against the pattern you define in regexp. php has both ereg and preg_match() functions. I’d suggest using preg_match() as there’s more documentation for this style of regex. An example
You’ve already got a working answer but just in case you are curious what was wrong with your original approach, the answer is that you need parentheses around your alternation otherwise the (\.|$) is only required if the number is less than 200.
You want the content of the first capture group.
Try this:
You have to use a negative lookahead assertion. You could for example use the following. If this does not work in your editor, try this. It is tested to work in ruby and javascript:
grep -v is your friend: -v, –invert-match select non-matching lines Also check out the related -L (the complement of -l). -L, –files-without-match only print FILE names containing no match