This will do it.

(\d\d\d-?\s?\d\d\d-?\s?\d\d\d\d\s?)?(x\d\d\d\d)?

or shorter equivalent:

(\d{3}-?\s?\d{3}-?\s?\d{4}\s?)?(x\d{4})?

You want to match the full phone number, optionally with space/dash, and make that whole thing optional, then include extension, and make that optional too.

Hi Kevin, · You might first look here for a quick tutorial on using the method string.match() with regex: JavaScript String match() Method · The match() method returns an array of all matches found, in your case you want there to only be one (and only one).   The trick then is getting your regex expression right for your requirements. · Here is a great RegEx reference sheet:   Regular Expressions - Dzone Refcardz · Now, down to brass tacks... here are a couple of examples on how to use regex and match() for your purposes: · function validatePhoneNumber(phoneValue){ · var strPhMatches = phoneValue.match(/^\d{3}-\d{3}-\d{4}$/); · if(strPhMatches!==null){ · return true; · } · else{ · alert("Invalid Phone Number"); · return false; · function validateExtension(extValue){ · var strExtMatches = extValue.match(/^x\d{4}$/i); · if(strExtMatches!==null){ · var phoneTempVar = strExtMatches[0].replace(/x/i, ''); · g_form.setValue('u_phone_number_extension', phoneTempVar); · g_form.clearValue('u_phone_number_extension'); · alert("Invalid Extension"); · Thanks, · -Brian · View solution in original post

You may try:

^\((\d{3})\)\s*(\d{3})-(\d{4})(?: ext(\d{5}))?$

Explanation of the above regex:

• ^, $ - Represents start and end of the line respectively.

• \((\d{3})\) - Represents first capturing group matching the digits inside ().

• \s* - Matches a white-space character zero or more times.

• (\d{3})- - Represents second capturing group capturing exactly 3 digits followed by a -.

• (\d{4}) - Represents third capturing group matching the digits exactly 4 times.

• (?: ext(\d{5}))? -

  • (?: Represents a non capturing group
  • ext - Followed by a space and literal ext.
  • (\d{5}) - Represents digits exactly 5 times.
  • ) - Closing of the non-captured group.
  • ? - Represents the quantifier making the whole non-captured group optional.

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You can find the sample demo of the above regex in here.

Powershell Commands:

PS C:\Path\To\MyDesktop> $input_path='C:\Path\To\MyDesktop\InputFile.txt'
PS C:\Path\To\MyDesktop> $output_path='C:\Path\To\MyDesktop\outFile.txt'
PS C:\Path\To\MyDesktop> $regex='^\((\d{3})\)\s*(\d{3})-(\d{4})(?: ext(\d{5}))?$'
PS C:\Path\To\MyDesktop> select-string -Path $input_path -Pattern $regex -AllMatches | % { "Phone Number: $($_.matches.groups[1])$($_.matches.groups[2])$($_.matches.groups[3])             Extension: $($_.matches.groups[4])" } > $output_path

Sample Result:

The easiest way to match both

^\([0-9]{3}\)[0-9]{3}-[0-9]{4}$

and

^[0-9]{3}-[0-9]{3}-[0-9]{4}$

is to use alternation ((...|...)): specify them as two mostly-separate options:

^(\([0-9]{3}\)|[0-9]{3}-)[0-9]{3}-[0-9]{4}$

By the way, when Americans put the area code in parentheses, we actually put a space after that; for example, I'd write (123) 123-1234, not (123)123-1234. So you might want to write:

^(\([0-9]{3}\) |[0-9]{3}-)[0-9]{3}-[0-9]{4}$

(Though it's probably best to explicitly demonstrate the format that you expect phone numbers to be in.)