How do you set a variable to NULL in PHP?
In PHP, a variable with no value is said to be of null data type. Such a variable has a value defined as NULL. A variable can be explicitly assigned NULL or its value been set to null by using unset() function.
Is NULL variable PHP?
The is_null() function checks whether a variable is NULL or not. This function returns true (1) if the variable is NULL, otherwise it returns false/nothing.
Can we use NULL in PHP?
Null is a special data type in PHP which can have only one value that is NULL. Any variable can be empty by setting the value NULL to the variable.
How check variable is not NULL in PHP?
The isset() function is an inbuilt function in PHP which checks whether a variable is set and is not NULL. This function also checks if a declared variable, array or array key has null value, if it does, isset() returns false, it returns true in all other possible cases.
How do you make a variable null?
A variable is considered to be null if:
- it has been assigned the constant null .
- it has not been set to any value yet.
- it has been unset().
What type of variable is null?
NULL is a special variable of type Undefined. Unlike a variable that is truly undefined, the value ! NULL can be assigned to other variables and used in comparisons.
Is empty or null PHP?
PHP empty() vs. The empty() function returns true if the value of a variable evaluates to false . This could mean the empty string, NULL , the integer 0 , or an array with no elements. On the other hand, is_null() will return true only if the variable has the value NULL .
Does empty check for NULL PHP?
empty() This function checks whether a variable evaluates to what PHP sees as a “falsy”(a.k.a empty) value. This being said, a variable is empty if it’s undefined, null, false, 0 or an empty string.