What is set and unset in php?
❮ PHP Variable Handling Reference Show ExampleUnset variables: $a = "Hello world!"; Try it Yourself » Definition and UsageThe unset() function unsets a variable. SyntaxParameter Values
Technical Details
❮ PHP Variable Handling Reference (PHP 4, PHP 5, PHP 7, PHP 8) unset — Unset a given variable DescriptionThe behavior of unset() inside of a function can vary depending on what type of variable you are attempting to destroy. If a globalized variable is unset() inside of a function, only the local variable is destroyed. The variable in the calling environment will retain the same value as before unset() was called.
The above example will output: To unset() a global variable inside of a function, then use the $GLOBALS array to do so:
If a variable that is PASSED BY REFERENCE is unset() inside of a function, only the local variable is destroyed. The variable in the calling environment will retain the same value as before unset() was called.
The above example will output: If a static variable is unset() inside of a function, unset() destroys the variable only in the context of the rest of a function. Following calls will restore the previous value of a variable.
The above example will output: Before unset: 1, after unset: 23 Before unset: 2, after unset: 23 Before unset: 3, after unset: 23 Parametersvar The variable to be unset. vars Further variables. Return ValuesNo value is returned. ExamplesExample #1 unset() example
Example #2 Using
The above example will output: Notes
See Also
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remove_element (&$array, $key) // pass array by reference phpmanual at kennel17 dot co dot uk ¶ 12 years ago
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bar(){ What is unset () in PHP?unset() destroys the specified variables. The behavior of unset() inside of a function can vary depending on what type of variable you are attempting to destroy. If a globalized variable is unset() inside of a function, only the local variable is destroyed.
What is the use of isset () and unset () functions?Determine if a variable is considered set, this means if a variable is declared and is different than null . If a variable has been unset with the unset() function, it is no longer considered to be set. isset() will return false when checking a variable that has been assigned to null .
What is isset and unset in PHP?PHP isset() Function
This function returns true if the variable exists and is not NULL, otherwise it returns false. Note: If multiple variables are supplied, then this function will return true only if all of the variables are set. Tip: A variable can be unset with the unset() function.
Is unset variable used in PHP?PHP | unset() Function
The unset() function is an inbuilt function in PHP which is used to unset a specified variable.
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