PHP Validation Functions Tutorial
Notes:
PHP Validation Functions:
- allow us to test or validate; whether a given data value is of type integer, double etc.
where:
data value can be a literal, variable name or constant name
is_integer(data value):bool
- checks whether the data value is of type integer
is_double(data value):bool
- checks whether the data value is of type double
is_numeric(data value):bool
- checks whether the data value is of type integer or double
is_bool(data value):bool
- checks whether the data value is of type boolean
is_string(data value):bool
- checks whether the data value is of type string
is_array(data value):bool
- checks whether the data value is of type array
is_object(data value):bool
- checks whether the data value is of type object
is_null(data value):bool
- checks whether the data value is of type NULL
is_resource(data value):bool
- checks whether the data value is of type resource
isset(data value):bool
- checks whether the data value is except NULL
empty(data value):bool
- checks whether the data value is 0, 0.0, "", "0", false, NULL, empty array
Example Code:
<?php
echo (is_integer(4)) ? "yes" : "no";
echo "<br/>";
echo (is_double(4.5)) ? "yes" : "no";
echo "<br/>";
echo (is_numeric(4)) ? "yes" : "no";
echo "<br/>";
echo (is_bool(true)) ? "yes" : "no";
echo "<br/>";
echo (is_string("Manjunath")) ? "yes" : "no";
echo "<br/>";
$names = array("Rama","Ravi");
echo (is_array($names)) ? "yes" : "no";
echo "<br/>";
class Point
{
}
$point1 = new Point();
echo (is_object($point1)) ? "yes" : "no";
echo "<br/>";
$point1 = null;
echo (is_null($point1)) ? "yes" : "no";
echo "<br/>";
$file = fopen("index.php","r");
echo (is_resource($file)) ? "yes" : "no";
echo "<br/>";
$playerScore=10;
echo (isset($playerScore)) ? "yes" : "no";
echo "<br/>";
$playerSpeed=10;
echo (empty($playerSpeed)) ? "yes" : "no";
echo "<br/>";
?>
Interview Questions:
1. PHP stands for ______________
a. Hypertext Preprocessor
b. Preprocessor Hypertext
c. Personal Home Processor
d. Personal Hypertext processor
Ans: a
