Question

I want to validate that the user has entered a comma separated list of words only using regex, will this work/is there a better way:

 $match = "#^([^0-9 A-z])(,\s|$))+$#";

This is not for parsing, as I will use explode for that, it is merely to validate that the user has correctly understood that values should be separated with commas.

Answer 1

I don’t know what the separate values should look like, but perhaps this is something that can help you:

$value = '[0-9 A-Z]+';
$match = "~^$value(,$value)*$~i";

When you know what your values should look like you can change $value.

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Update

Taken this comment from the question

I was trying to disallow 0-9 but allow a-Z, because, as I said it should be a list of words only, no spaces, just a list of single words.

Just change $value

$value = '[A-Z]+';

Note, that I use the i-modifier in $match, that will include all lowercase letters too.

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However, "real" csv allows a little bit more than this, for example you can put quotes around every value. I would recommend that you parse the line and then test every single value

$values = str_getcsv($line);
$valid = true;
foreach ($values as $value) {
  $valid = $valid && isValid($value);
}

str_getcsv()