note 105178 modified in function.in-array by danbrown

Be VERY careful about testing for strings in arrays that might also contain integers. In this snippet, the range() function turns the numeric values into integers, and loose data typing finds a match with zero. Outputs: PHP in_array() FOUND @#%?!! @#%?!! == 0 AT POSITION 26 BECAUSE OF LOOSE TYPE <?php // RAY_temp_in_array.php error_reporting(E_ALL); echo "<pre>"; // THE ALLOWABLE SELECTIONS $alpha = range('A','Z'); $alpha = array_merge($alpha, range('0', '9')); // LOOK FOR A BOGUS SELECTION $str = '@#%?!!'; if (in_array($str, $alpha)) { echo "PHP in_array() FOUND $str "; } else { echo "$str IS NOT IN ARRAY"; } // SEARCH THE ARRAY FOR THE KEY OF THE STRING $key = array_search($str, $alpha); echo "<br/>$str == $alpha[$key] AT POSITION $key"; if ($str == 0) echo " BECAUSE OF LOOSE TYPE"; ?> --was-- Be VERY careful about testing for strings in arrays that might also contain integers. In this snippet, the range() function turns the numeric values into integers, and loose data typing finds a match with zero. Outputs: PHP in_array() FOUND @#%?!! @#%?!! == 0 AT POSITION 26 BECAUSE OF LOOSE TYPE <?php // RAY_temp_in_array.php error_reporting(E_ALL); echo "<pre>"; // THE ALLOWABLE SELECTIONS $alpha = range('A','Z'); $alpha = array_merge($alpha, range('0', '9')); // LOOK FOR A BOGUS SELECTION $str = '@#%?!!'; if (in_array($str, $alpha)) { echo "PHP in_array() FOUND $str "; } else { echo "$str IS NOT IN ARRAY"; } // SEARCH THE ARRAY FOR THE KEY OF THE STRING $key = array_search($str, $alpha); echo "<br/>$str == $alpha[$key] AT POSITION $key"; if ($str == 0) echo " BECAUSE OF LOOSE TYPE"; http://php.net/manual/en/function.in-array.php