Which Values Are Considered Falsy in PHP?

In PHP, the following values are considered falsy:

• Boolean false;
• Integer 0;
• Float 0.0 and -0.0;
• Empty String;
• String "0";
• Array with no elements, [];
• NULL type;
• SimpleXML objects that are created from empty elements (i.e. elements that have no children and attributes).

These values evaluate to a boolean false when:

1. They're explicitly converted to a boolean (for example by casting);
2. An operator, function or control structure requires a boolean argument (in which case the value is converted to a boolean implicitly/automatically).