php 0 = = ' false ', 0 = = False will be equal, and false!= ' false reason.

First look at a special case:
Var_dump (0 = = ' false '), returns BOOL (true), PHP determines 0 equals any string, Var_dump (0=== ' false '), returns BOOL (false), and the congruent contains type and value to be equal.
Var_dump (0 = false), returning bool (true),

Reasons for the above results (translated from the official PHP document): 1. For bool: When you output a bool or use it in a statement , it is converted to a number, true to 1 , and false to 0. . For example $a = true; Var_dump ($a + 1), return (int) 2; The $a is converted to 1, and the sum is 2;
A bool variable expresses a true value, not an expression of 0 or 1; A Boolean is not a symbolic constant.
2, String: PHP will always automatically try to convert the string into a numeric type. For example Var_dump (' abc ' +3 '), returns INT (3) , first ' abc ' is converted to the number 0, the addition becomes 3;
Methods for detecting the types of variables:
1, Var_dump ($param), returns the type and value of the variable. 2. Use Is_int (), Is_bool (), is_string (); function, return True and false,
A common type conversion method.
Variable $param integral (int) $param character type (String) $param Boolean (bool) $param another way to convert to a Boolean: $a =!5, $a to false, $a =!! 5, $a is true;