Pattern matching problems using eregi 1

[frozenpeas]

Hi,

The following code currently accepts whatever the value of the variable is, as long as it contains a letter. It will reject "9" but will accept "a9". I need to allow only letters - am I using this properly?

Thanks.

$patternAlpha = "[a-z]";
if(!eregi($patternAlpha,$namef)){
			$errorFlag = 1;
			$errorMsg .= "The First Name field may contain only letters.<br>";
		}

frozenpeas

 

[DRJ478]

First of all, I would recommend that you use PCRE regular expressions.
There are a few things you need to do:
1. Patterns should have pattern delimiters, usually people use forward slashes, e.g.

$patternAlpha = "/[a-z]/"l

2. Your logic is a bit flawed. Your epressions says basically if there is any alpha character in the string, it passes the test. You need to extend the definition and tighten the pattern:

$pattern = "/^[a-z]+$/i";
if (!preg_match($pattern, $namef)){
   $errorFlag = true;
   $errorMsg .= "Blah blah blah.";
}

Explanation of the pattern:
/ -> initial pattern delimiter
^ -> start of the subject (the string to be examined)
[ -> character class definition start
a-z -> any alpha from a to z
] -> character class definition end
+ -> one or more (excludes empty strings)
$ -> end of the subject
/ -> end pattern delimiter
i -> be case insensitive, covers a-z and A-Z

 

[frozenpeas]

Beautiful reply. Thank you!

frozenpeas