php in_array syntax

bool in_array ( mixed $needle , array $haystack [, bool $strict ] ) The return value is straight or false

var_dump(in_array(0, array('s' ));

The result of this sentence is bool(true).

Because in_array will compare 0 and 's', 0 is a number type and 's' is a string type. According to the "comparison operators" in the manual It can be seen from the explanation in Chapter that when number and string are compared, the string type will be converted to number first, and then the comparison operation will be performed. The result of converting 's' to number is 0, and the result of 0 == 0 is true. Therefore, the result of in_array(0, array('s', 'ss')) is also true

If the third parameter strict of in_array is set to true, the comparison will determine whether the value and type are both Equivalent. If they are equivalent, it will return true, otherwise it will return false.

About php in_array syntax

bool in_array (mixed $needle, array $haystack [, bool $strict ] ) The return value is straight or false

$a = array('1.10', 12.4, 1.13);  

if (in_array('12.4', $a, true)) {  
     echo "'12.4' found with strict checkn";  
 }  

if (in_array(1.13, $a, true)) {  
     echo "1.13 found with strict checkn";  
 }

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