Very Very Very Simple Question

[Designer_101]

Hi

I've quite a while into my PHP course now however I seem to have missed something, I keep seeing things like:

if ($variable_name) {..

It's quite scary because I should really know this and it seems extremely basic so sorry for the questions simplicity.
Is it asking wether the statment is true?
If the variable exists?

Thankyou in advanced

[kadimi]

The variable exists and is not set to one of these:
* "" (an empty string)
* 0 (0 as an integer)
* "0" (0 as a string)
* NULL
* FALSE
* array() (an empty array)
* var $var; (a variable declared, but without a value in a class)
...

[nav33n]

if($variable) {
//statements
}

This simply means, if(true) . If a variable is set and if doesn't have values 0,false,'', it will execute corresponding statements.
Example,

<?php
$a = NULL;
if($a) {
 echo "$a is true<br />";
} else {
echo "$a is false<br />";
}

$a="";
if($a) {
 echo "$a is true<br />";
} else {
echo "$a is false<br />";
}

$a=1;
if($a) {
 echo "$a is true<br />";
} else {
echo "$a is false<br />";
}

$a=0;
if($a) {
 echo "$a is true<br />";
} else {
echo "$a is false<br />";
}

$a=true;
if($a) {
 echo "$a is true<br />";
} else {
echo "$a is false<br />";
}

$a=false;
if($a) {
 echo "$a is true<br />";
} else {
echo "$a is false<br />";
}

$a=100;
if($a) {
 echo "$a is true<br />";
} else {
echo "$a is false<br />";
}

$a=array("10","20");
if($a) {
 echo "$a is true<br />";
} else {
echo "$a is false<br />";
}

$a = "some string";
if($a) {
 echo "$a is true<br />";
} else {
echo "$a is false<br />";
}
?>

[Designer_101]

Thankyou very much.