PHP empty() function : The php empty() function is used to check if variable is empty or not. The empty() function returns true or false.
<?Php $my_var=""; if(empty($my_var)){echo " True Variable is empty, ";} else {echo " False "; } $my_var="0"; if(empty($my_var)){echo " True Variable is empty, ";} else {echo " False "; } $my_var=0; if(empty($my_var)){echo " True Variable is empty, ";}...
PHP - Checking an Empty Array To check whetheran array is empty or not, we can use a built-in functionempty(), in other cases where we want to check if a given variable is empty or not, it can also be used. It returns a Boolean response based on the condition that if the given...
if( isset($_GET['user']) ){ echo ' welcome to the website ' . $_GET['user']; } ?> 1. 2. 3. 4. 5. 6. 测试: http://localhost/isset.php?user=zxl add.php <?php if( isset($_GET['num1']) and isset($_GET['num2']) ){ $num1 = $_GET['num1']; $num...
if(isset($var)){ echo$var; }else{ echo"Variable does not exist"; } ?> In the above example, we have taken a variable. Using the PHP isset() we have first checked if the variable exists or not. If it returns TRUE or the variable exists it will show the variable value on the we...
The-zoperator returnstrueif a string variable is null or empty. How the use the-zBash Operator Afterdeclaring a string variable, use the-zoperator in anif statementto check whether a string is empty or not: MY_STRING="" if [ -z $MYSTRING ] ...
JavaScript Define a Function to Check If a Variable is a String 6 7 8 9 // Defining a function 10 function isString(myVar) { 11 return (typeof myVar === 'string'); 12 } 13 14 // Sample variables 15 var x = 10; 16 var y = true; 17 var z = "...
<?php$emptyArray=array();$isEmpty=empty($emptyArray);echo("The function has returned $isEmpty. \n");if(empty($emptyArray))echo("The array is empty.");?> We have stored the return value ofempty()function in$isEmptyvariable.
Hi, How can I check if a variable only has these characters: - number (0-9) - decimal point (.) - positive (+) - negative (-) - dollar ($) I tried is_numeric, but it doesn't like negative values... I need to add the variable value to another variable. I
If you want to check whether a variable has been initialized or defined (i.e. test whether a variable has been declared and assigned a value) you can use the typeof operator.The most important reason of using the typeof operator is that it does not throw the ReferenceError if the ...