recognizing and reading a new line character

[phpnewbie26]

In my program I have an if else statement where I'm trying to see if that line is a skipped line. My text is like this:

fruits

vegetables.

So it has to be able to know to skip to the next line if theres no text in that line.

if ($invalidcheck[0]=='\r\n'){
        $i++;
        }
 

but it doesn't seem to be reading it. Does anyone know how I can fix this? Also I was wondering if it is reasonable to try to do something like if the character isn't a-z, A-Z, and all symbols.
Thanks

[Atli]

Try using the trim and empty functions to check the value.

<?php
$value = "\r\n  ";
 
$value = trim($value);
if(empty($value)){
    echo "Empty";
}
else {
    echo "Not empty";
}
?>

@phpnewbie26
Whether it is reasonable to do, that's up to you, and whoever else is designing your application.

If it is, you can easily do that using regular expressions.
Like:

if(preg_match('/^[a-zA-Z]+$/i', $value))

This would only allow the $value to contain letters.
(And only letters... no numbers, spaces, question marks, etc...)

[phpnewbie26]

The trim and empty function worked perfectly. Thanks! I'm new to php so I wasn't even aware of that function.=)

[Markus]

@Atli
Shouldn't that be [^a-zA-Z0-9]? Or do they both work the same?

[Markus]

@phpnewbie26
You should try and use other options, instead of the preg_* functions as they're said to be pretty slow (the preg_* functions), although it's probably such a small difference it's pointless bringing it up (will have to benchmark it).

[Atli]

@Markus
Just different varieties.

Mine was like:

if(<only allowed chars found>) {
  // Do stuff
}
else {
  // Don't do stuff
}

But yours is more like:

if(<illegal chars found>) {
  // Don't do stuff
}
else {
  // Do stuff
}

Whitelist vs. Blacklist approaches... although in this case, with the ^ in the regex class, they are not so different.

[Atli]

@phpnewbie26
Glad it worked :)