regex - Read For Learn

Extract part of a regex match

Use ( ) in regexp and group(1) in python to retrieve the captured string (re.search will return None if it doesn’t find the result, so don’t use group() directly):

How is \\n and \\\n interpreted by the expanded regular expression?

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

Can a URL contain a semicolon and still be valid?

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

How to use regex with find command?

Note that you need to specify .*/ in the beginning because find matches the whole path. Example: My version of find:

Validate phone number with JavaScript

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

How to validate phone number using PHP?

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

grep using a character vector with multiple patterns

In addition to @Marek’s comment about not including fixed==TRUE, you also need to not have the spaces in your regular expression. It should be “A1|A9|A6”. You also mention that there are lots of patterns. Assuming that they are in a vector Then you can create your regular expression directly using paste and collapse = “|”.