Validation of text box

[rocky_88]

I'm unable to validate my text box which should contain only alphabets.

 

Here is the code

 

$string=preg_match("/^[a-zA-Z]+$/",$string);
if($string)
{
echo "Valid";
}
else
{
echo "Invalid";
}

 

Even though the textbox contains only alphabets, it shows invalid.

 

I dont know what i'm doing wrong here.

 

However, if I leave a space inside the character class, it validates the string.

I've checked the output of the string and there are no spaces what so ever, yet it shows invalid.

[Pikachu2000]

You'd be better with ctype_alpha for this.

[rocky_88]

@Pikachu2000

 

Thanks for that, it did the job.

 

Any idea as to what's the error in the code I mentioned?

[Pikachu2000]

I don't really know. I just copied/pasted your code, and it seems to work. What values of $string were you were testing it with?

[rocky_88]

@Pikachu2000

 

I tried random values.

 

It shows invalid for abcd xyz or anything that I enter.

[Pikachu2000]

This code uses your pattern; try it and see what results you get.

 

<?php
$strings = array('thisisastring', 'thishas9numbers', 'this has spaces', 'alsoaSTRING', 'special_%ch$arac#ter!s');
foreach( $strings as $string ) {
$valid = preg_match("/^[a-zA-Z]+$/",$string);
echo "<i>$string</i>";
if($valid) {
	echo " is Valid";
} else {
	echo " is Invalid";
}
echo '<br>';
}

[/code]

[rocky_88]

This is the output.

 

thisisastring is Valid

thishas9numbers is Invalid

this has spaces is Invalid

alsoaSTRING is Valid

special_%ch$arac#ter!s is Invalid

 

For my code, it shows invalid if I use regex and valid if I use ctype_alpha().

[Pikachu2000]

I think I see why you're having issues. If you are assigning the result of preg_match() to the $string variable, it's important to understand what values may be returned from preg_match() . . .

 

preg_match() returns the number of times pattern matches. That will be either 0 times (no match) or 1 time because preg_match() will stop searching after the first match. preg_match_all() on the contrary will continue until it reaches the end of subject. preg_match() returns FALSE if an error occurred.

[rocky_88]

I'm pretty sure that it does work that way as i'm validating other fields too using regex and they work just fine. Its just with this particular "alphabets only" condition.