PHP In_array Syntax

BOOL In_array (mixed $needle, array $haystack [, BOOL $strict]) 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 the number type, ' s ' is a string type, according to the description in the chapter "Comparison operators" in manual, when number and string are compared, The string type is first converted to number before the comparison operation. The result of ' s ' conversion to number is 0, and the result of 0 = = 0 is true, so the result of In_array (0, Array (' s ', ' SS ')) is also true

If the third parameter of In_array is set to True, the comparison will determine whether the value and type are equal. Returns true if all are equal, otherwise returns false.

About PHP In_array syntax

BOOL In_array (mixed $needle, array $haystack [, BOOL $strict]) 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";   }