CODEWITHSUNDEEP
phpregexpreg-match
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Reputation: 57286

preg_match: number-alphabets and commas only

How do I write a regular expression which matches number-alphabets and commas only?

I came out with this one below but it doesnt work - it accepts other punctuation marks as well!

# check for matches number-alphabets and commas only
  if(!preg_match('/([a-zA-Z0-9]|[a-zA-Z0-9\,])/', $cst_value))
  {
   $error = true;
   echo '<error elementid="usr_username" message="'.$cst_name.' - please use number-alphabets and commas only."/>';
  }

Many thanks, Lau

Upvotes: 8

Views: 32376

Answers (3)

Phill Pafford
Phill Pafford

Reputation: 85378

Well this adds a couple more characters like underscore

/^[\w,]*$/

But this should work

/^[a-zA-Z0-9,]*$/

Upvotes: 1

NullUserException
NullUserException

Reputation: 85478

You want:

/^[a-zA-Z0-9,]+$/

You need the start ^ and end $ of string anchors. Without them the regex engine will look for any of those characters in the string and if it finds one, it will call it a day and say there's a match. With the anchors, it forces the engine to look at the whole string. Basically:

  • /[a-zA-Z0-9,]+/ matches if any of the characters are alphanumeric + comma.
  • /^[a-zA-Z0-9,]+$/ matches if all of the characters are alphanumeric + comma.

Upvotes: 19

codaddict
codaddict

Reputation: 455440

if(preg_match('/^[0-9a-z,]+$/i', $cst_value)) {
  // valid input..contains only alphabet,number and comma.
}else{
  // invalid
}

We pass the following to preg_match : /^[0-9a-z,]+$/i

Explanation:

  • / : regex delimiters.
  • ^ : start anchor
  • [..] : Char class
  • 0-9 : any digit
  • a-z : any alphabet
  • , : a comma. comma is not a regex metachar, so you need not escape it
  • + : quantifier for one or more. If an empty input is considered valid, change + to *
  • $ : end anchor
  • i : to make the matching case insensitive.

Upvotes: 10

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