string to boolean in php code example

Example 1: cast to boolean php

/** filter_var - Filters a variable with a specific filter **/
$boolvar = filter_var('true', FILTER_VALIDATE_BOOLEAN);
/** boolval - Get the boolean value of a variable PHP 5 >= */
$boolvar = boolval ('true');
// And literally with a ternary operator but I can't recommend it
$boolvar = ($string === 'true')  ? true: false; 

/** We can convert any variable to boolean
--- using the (bool) or (boolean) keyword -----
*** But we are talking about conversion not casting ***
-   So any String whose length is greater than 0 is true 
-   and any number other than 0 is true
**/
echo $boolvar = (bool)1; //return true
echo $boolvar = (bool)"true"; //return true
echo $boolvar = (bool)"false"; //return true
echo $boolvar = (bool)0; //return false
echo $boolvar = (bool)""; //return false

var_dump((bool) 0);//return false 
var_dump((bool) "");//return false

Example 2: php convert string to boolean

/**
 * Strings always evaluate to boolean true unless they have a
 * value that's considered "empty" by PHP (taken from the
 * documentation for empty):
 * "" (an empty string) evaluates as false.
 * "0" (0 as a string) evaulates as false.
 * If you need to set a boolean based on the text value of a
 * string, then you'll need to check for the presence or
 * otherwise of that value.
 */
$boolean = $string === 'true' ? true: false;

Example 3: php convert to boolean

// (PHP 5 >= 5.5.0, PHP 7)
// boolval — Get the boolean value of a variable
boolval ( mixed $var ) : bool
// Returns the boolean value of var.

Example 4: php boolean to string

$converted_res = $res ? 'true' : 'false';

Example 5: php boolean

Booleans can be one of two constants:
true
false
These values are not case sensitive, therefore true is the same as TRUE

booleans are also often used in control structures, either directly or as
a result of an operation. For example:

if ($waterDrankToday > 3.7) {
 echo "Good work staying hydrated!";
 if ($havingABadDay)
   hug();
}
else
  echo "You should drink more water";