Why "switch(true){}" in php with a strange logic?

Question

switch(false) {
    case 'blogHitd':
        echo('ddd');
        break;
    case false:
        echo('bbbb');
        break;
    default:
        echo 'alert("error action");';
 }

-------output------

bbbb

switch(true) {
    case 'blogHitd':
        echo('ddd');        
        break;
    case true:
        echo('bbbb');
        break;
     default:
        echo 'alert("error action");';
 }

-------a strange output-------

ddd

Why, when I pass the value of true it will always select the first one?

Answer 1

From the PHP documentation on Booleans:

When converting to boolean, the following values are considered FALSE:

• the boolean FALSE itself
• the integer 0 (zero)
• the float 0.0 (zero)
• the empty string, and the string "0"
• an array with zero elements
• an object with zero member variables (PHP 4 only)
• the special type NULL (including unset variables
• SimpleXML objects created from empty tags

Every other value is considered TRUE (including any resource).

The last sentence of this quoted passage is the line of interest in your case.