Chuck's Musings

yep, that’s ternary operation

the equal signs is a special kind of comparison, which means “must be equal to and must be of the same data type”

because PHP has data type juggling, which means if:
$value = 0;

this means that:

if($value == FALSE) will evaluate as TRUE, since 0 is also equal to FALSE,

but if($value === FALSE) will evaluate to FALSE because 0 is not a boolean value

@nil acuna

We call that “type juggling” in PHP, here’s a reference:
http://us3.php.net/manual/en/language.types.type-juggling.php

The variables are treated contextually, e.g. if you add “100″ (a string) to 100 (an integer), you get 200 (integer). But if you concatenate “100″ and 100, you get “100100″ (string).

Type casting can also be done if you’re used to it.

nil acuna :

say $value = 1 + 1 ; would imply $value is a number. then if ($value == FALSE) will not behave as expected. php is still very very voodoo to me, but i’m slowly up picking interest!

if($value == TRUE)

- is the same as writing if($value)

this means $value must contain any value which is not the equivalent of FALSE, meaning, all the following values will cause that condition to evaluate as true:

$value = 1; // integer
$value = ‘chuck’; // string
$value = TRUE; // boolean
$value = ‘chuck’ . ‘ cerrillo’; // string concatenation
$value = 100 + 1; // integer

while all of the following will evaluate as FALSE:

$value = FALSE; // boolean FALSE
$value = 0; // 0 = FALSE
$value = ‘0′; // ‘0′ => 0 = FALSE
$value = NULL; // since there’s no value to check, it’s FALSE

but if you instead used this:

if($value === TRUE)

only $value = TRUE; will evaluate as TRUE

Here’s a practical example for that… if you are to perform string matching and you wanted to find the offset of the matched string (remember strcmp during highschool days?)

Say, we have this string:

$string = “I would like to buy a hamburger”;

…and you wanted to find… say… “hamburger”. We’ll be using the strpos() function to get the offset: http://us3.php.net/manual/en/function.strpos.php
Note: Returns the position as an integer. If needle is not found, strpos() will return boolean FALSE.

so if you do this:

$string = “I would like to buy a hamburger”;
if( strpos($string,’hamburger’) == FALSE )
echo ‘There is no hamburger…’;
else
echo ‘We found a hamburger!’;

This will display “We found a hamburger!” because the string ‘hamburger’ is found at position 22. But what if we had this string instead?

$string = “hamburger and fries is a good combination”;

Using the same condition, this will display “Theere is no hamburger…”. Even though we can find it at position 0 of $string. Remember type juggling. 0 = FALSE.

so if you do it this way instead

$string = “hamburger and fries is a good combination”;
if( strpos($string,’hamburger’) === FALSE )
echo ‘There is no hamburger…’;
else
echo ‘We found a hamburger!’;

It would only evaluate as FALSE when strpos does not find the string.

sure