Php function with null parameters

Send parameter to function in php can null

This is documented in the section in the manual about Type Declarations: Solution 2: Starting from PHP 7.1, nullable types are available, as both function return types and parameters. Solution 3: Try: Check out PHP function arguments.

PHP Functions, null default parameters

When you declare a function like this:

testfunction($param1, $param2, $param3, $param4=NULL) < //do stuff >

You’re telling PHP that $param4 already has a value, so when that function is called, a value is already assigned to it. It doesn’t expect you to send an argument for that parameter because a default one has already been assigned.

It therefore knows the function will be able to operate (to a certain extent) as it should. It’s useful for making optional parameters.

However when you declare a function as this:

testfunction($param1, $param2, $param3, $param4) < //do stuff >

PHP Expects you to send through that argument ($param4), because without it, the function won’t be able to accomplish what you’ve set it out to do, at least so PHP assumes, because you would never create a function with 4 parameters where not one of them are used in the function body.

Optional parameters in PHP function without considering, Aug 28, 2018 at 19:57. 1. yes. a function (or you as a coder) have two possibilities to distiguish passed in parameters: order or type. Or you use a construction as @ChrisForrence described in his answer. So the answer to your question is: NO. But there are workarounds you can find in the answers. – Jeff.

PHP by-reference parameters and default null

It’s because you can’t have a reference to null.

You can have a reference to a variable that contains null — that is exactly what the default value does. Or you can pass in null as a literal value — but since you want an out parameter this is not possible here.

While you must create a dummy variable for by-ref arguments if you want to pass NULL explicitly, you don’t have to create that variable on a separate line. You can use an assignment expression like $dummy=NULL directly as a function argument:

I just found out this myself, and I’m quite in shock o_O!

This is what the PHP documentation says:

function makecoffee($type = "cappuccino") < return "Making a cup of $type.\n"; >echo makecoffee(); // returns "Making a cup of cappuccino." echo makecoffee(null); // returns "Making a cup of ." echo makecoffee("espresso"); // returns "Making a cup of espresso." 

I would have expected makecoffee(null) to return «Making a cup of cappuccino.». One work-around I have used is to check inside the function if the argument is null:

function makecoffee($type = null) < if (is_null($type))< $type = "capuccino"; >return "Making a cup of $type.\n"; > 

Now makecoffee(null) returns «Making a cup of cappuccino.»

(I realize this doesn’t actually solve the Zend-related question, but it might be useful to some. )

Php — Sending default parameter as null and use default, In php you cannot declare more than 1 parameter with default value in your function. Php could not know wich param you do not give if you have multiple default value In your case, you give the param, with null value. That’s a lot different ! So, you can use the following :

PHP Function with Optional Parameters

What I have done in this case is pass an array, where the key is the parameter name, and the value is the value.

$optional = array( "param" => $param1, "param2" => $param2 ); function func($required, $requiredTwo, $optional) < if(isset($optional["param2"])) < doWork(); >> 

Make the function take one parameter: an array. Pass in the actual parameters as values in the array.

Edit: the link in Pekka’s comment just about sums it up.

To accomplish what you want, use an array Like Rabbot said (though this can become a pain to document/maintain if used excessively). Or just use the traditional optional args.

//My function with tons of optional params function my_func($req_a, $req_b, $opt_a = NULL, $opt_b = NULL, $opt_c = NULL) < //Do stuff >my_func('Hi', 'World', null, null, 'Red'); 

However, I usually find that when I start writing a function/method with that many arguments — more often than not it is a code smell, and can be re-factored/abstracted into something much cleaner.

//Specialization of my_func - assuming my_func itself cannot be refactored function my_color_func($reg_a, $reg_b, $opt = 'Red') < return my_func($reg_a, $reg_b, null, null, $opt); >my_color_func('Hi', 'World'); my_color_func('Hello', 'Universe', 'Green'); 

Php — Is passing NULL param exactly the same as passing, If I call doSomething(15, null), I’ll get result (15,NULL). Problem is when I need to set only second (or third, fourth, etc. on more complex functions) parameter like doSomething(, 30) which is not possible in php. It must be set to null and then in function must be used coalescing operator. –

Cannot pass null argument when using type hinting

PHP 7.1 or newer (released 2nd December 2016)

You can explicitly declare a variable to be null with this syntax

$this->foo(new Type()); // ok $this->foo(null); // ok $this->foo(); // error 

So, if you want an optional argument you can follow the convention Type $t = null whereas if you need to make an argument accept both null and its type, you can follow above example.

PHP 7.0 or older

You have to add a default value like

That way, you can pass it a null value.

This is documented in the section in the manual about Type Declarations:

The declaration can be made to accept NULL values if the default value of the parameter is set to NULL .

Starting from PHP 7.1, nullable types are available, as both function return types and parameters. The type ?T can have values of the specified Type T , or null .

So, your function could look like this:

As soon as you can work with PHP 7.1, this notation should be preferred over function foo(Type $t = null) , because it still forces the caller to explicitly specify an argument for the parameter $t .

Php — Cannot pass null argument when using type hinting, In other languages null has the ability to be of any type thus making null a valid argument in this case. 2: Php is using a default value for an argument to specify that null is allowable, this is obscure and it makes a mandatory parameter impossible even if the developer wants to force a null to be explicitly …

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Php function with null parameters

To experiment on performance of pass-by-reference and pass-by-value, I used this script. Conclusions are below.

#!/usr/bin/php
function sum ( $array , $max ) < //For Reference, use: "&$array"
$sum = 0 ;
for ( $i = 0 ; $i < 2 ; $i ++)#$array[$i]++; //Uncomment this line to modify the array within the function.
$sum += $array [ $i ];
>
return ( $sum );
>

$max = 1E7 //10 M data points.
$data = range ( 0 , $max , 1 );

$start = microtime ( true );
for ( $x = 0 ; $x < 100 ; $x ++)$sum = sum ( $data , $max );
>
$end = microtime ( true );
echo «Time: » .( $end — $start ). » s\n» ;

/* Run times:
# PASS BY MODIFIED? Time
— ——- ——— —-
1 value no 56 us
2 reference no 58 us

3 valuue yes 129 s
4 reference yes 66 us

1. PHP is already smart about zero-copy / copy-on-write. A function call does NOT copy the data unless it needs to; the data is
only copied on write. That’s why #1 and #2 take similar times, whereas #3 takes 2 million times longer than #4.
[You never need to use &$array to ask the compiler to do a zero-copy optimisation; it can work that out for itself.]

2. You do use &$array to tell the compiler «it is OK for the function to over-write my argument in place, I don’t need the original
any more.» This can make a huge difference to performance when we have large amounts of memory to copy.
(This is the only way it is done in C, arrays are always passed as pointers)

3. The other use of & is as a way to specify where data should be *returned*. (e.g. as used by exec() ).
(This is a C-like way of passing pointers for outputs, whereas PHP functions normally return complex types, or multiple answers
in an array)

5. Sometimes, pass by reference could be at the choice of the caller, NOT the function definitition. PHP doesn’t allow it, but it
would be meaningful for the caller to decide to pass data in as a reference. i.e. «I’m done with the variable, it’s OK to stomp
on it in memory».
*/
?>

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Passing Null Parameters to Functions in PHP: Best Practices and Type Declarations

Learn how to pass null values to functions in PHP, handle null values effectively, and use type declarations for better code reliability.

• Introduction
• Passing Null to a Function in PHP
• Handling Null Values in Functions
• Passing Null to Non-Nullable Parameters in PHP
• Type Declarations in PHP Functions
• Best Practices for Handling Null Values in PHP
• Other helpful code examples for passing null parameters to PHP functions
• Conclusion
• Can a function parameter be null?
• How do you pass a null as a parameter?
• How to pass parameters to a function in PHP?
• How to pass null value in function PHP?

As a PHP developer, you may encounter situations where you need to pass null as a parameter to a function. In this blog post, we will discuss the best practices for passing null parameters to functions in PHP and handling null values in functions.

Introduction

When working with PHP, it is essential to handle null values effectively in functions. In this blog post, we aim to provide a comprehensive guide on how to pass null as a parameter to a function in PHP and how to handle null values in functions.

Passing Null to a Function in PHP

To pass null as a parameter to a function in PHP, you can simply omit the argument or explicitly pass null . When you omit the argument, PHP treats it as if it was explicitly passed as null . However, it is recommended to explicitly pass null to make the code more readable.

Here is an example of how to pass null to a function in PHP:

function myFunction($param) < // Code to handle $param >myFunction(null); 

It is important to note that passing null is different from not passing any argument. When you don’t pass any argument, PHP treats the parameter as undefined. However, when you pass null, PHP interprets it as a defined null value.

Handling Null Values in Functions

When working with functions that accept null parameters, you must handle null values effectively. You can use the null coalescing operator ( ?? ) to provide a default value when the parameter is null.

Here is an example of how to handle null values in a function:

function myFunction($param) < $value = $param ?? 'default value'; // Code to handle $value >myFunction(null); 

In the above example, the $value variable is assigned the value of $param if it is not null. Otherwise, it is assigned the default value of ‘default value’ .

Passing Null to Non-Nullable Parameters in PHP

In PHP 8.1 and later, passing null to a non-nullable parameter results in a fatal type error. This means that if a function expects a non-nullable parameter, you cannot pass null as an argument.

Here is an example of what happens when you pass null to a non-nullable parameter:

function myFunction(string $param) < // Code to handle $param >myFunction(null); // Fatal error: Uncaught TypeError 

To avoid this error, you can use type declarations in php functions.

Type Declarations in PHP Functions

Type declarations allow you to specify the type of a function argument or return value. In PHP 8.1 and later, you can mark type declarations as nullable by prefixing the type name with a question mark ( ? ). This indicates that the argument or return value can be either of the specified type or null.

Here is an example of how to use type declarations in PHP functions:

function myFunction(?string $param): ?string < // Code to handle $param return $param; >myFunction(null); // Returns null 

In the above example, the ?string type declaration indicates that the $param argument can be either a string or null. Similarly, the ?string return type declaration indicates that the function can return either a string or null.

Best Practices for Handling Null Values in PHP

When working with null values in php functions, it is important to follow best practices to ensure that your code is readable, maintainable, and bug-free. Here are some best practices for handling null values in PHP:

• Explicitly set default values to null: When using the null coalescing operator to handle null values, it is recommended to explicitly set the default value to null. This makes the code more readable and reduces the risk of bugs.
• Check for null values using $param === null or is_null($param) : When checking for null values, it is recommended to use the === operator or the is_null() function. This ensures that the comparison is strict and does not have any unexpected behavior.

Other helpful code examples for passing null parameters to PHP functions

In php, send parameter to function in php can null code example

function foo(?Type $t) < >this will result in$this->foo(new Type()); // ok $this->foo(null); // ok $this->foo(); // error

Conclusion

Passing null as a parameter to a function in PHP and handling null values in functions is an essential skill for PHP developers. By following the best practices discussed in this blog post, you can ensure that your code is readable, maintainable, and bug-free. Remember to always handle null values effectively in your PHP functions to avoid unexpected behavior and errors.

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