I am trying to rewrite some code to eliminate the call_user_func_array calls, and have the following code so far :
if($stmt = $this->_db->prepare($sql)) {
$bind_arguments = $this->params;
// remove first element (eg. 'ssiss')
$bind_arguments = array_shift($bind_arguments);
// execute query passing values
$res = $stmt->execute($bind_arguments);
}
Here is a var_export of $this->params :
array ( 0 => 's', 1 => 'admin', )
$res always evaluates to null when trying the above method. According to this comment, it appears that everything is correct, except my array has integer keys, and there is an additional , after the last element.
What do I need to do to format this array (removing the first element), to pass to the $stmt->execute method as the variable containing the array elements (this is not a static array. elements in it are modified by other methods in the class to add or remove elements from it).
First of all, to make things straight: you cannot pass an array to mysqli_execute() as this function accepts no parameters at all. What you really need is to pass an array to mysqli_bind_param()
However, the only way around call_user_func_array call is a splat operator available since PHP 5.6
function query($query, $params = NULL, $types = NULL)
{
$statement = $this->mysqli->prepare($select);
$types = $types ?: str_repeat('s', count($params));
$statement->bind_param($types, ...$params);
$statement->execute();
return $statement;
}
Yet the preferred and bullet-proof solution would be apparently switching to PDO, which indeed has the capability of sending an array with parameters right into execute().
Array should be associative array and key name should be column name of table and data should be value of key. Like the following:
$arr = [ 'column1' => 'value1', 'column2' => 'value2' ];
than use $res = $stmt->execute($arr);
The goal is to get some precise values of $_GET in a property of a class while:
removing any key not desired
defaulting values when keys are not defined
With this code in a file /request.php:
$req = new request();
var_dump($req);
class request {
private $Get;
function __construct() {
$this->Get = filter_input_array(INPUT_GET,array (
'menu'=>array (
'filter'=>FILTER_VALIDATE_INT,
'options'=>array (
'default'=>30,
),
),
));
}
}
from php's man page for filter_input_array() about the third parameter (true by default):
Add missing keys as NULL to the return value.
I would expect that calling domain.com/request.php would yield a defaulted [sic] array with the integer 30 as menu's value. however when no $_GET are defined (that is, when there's no character after a question mark in the url) filter_input_array returns null therefore the var_dump is this:
object(request)#1 (1) { ["Get":"request":private]=> NULL }
however when $_GET is defined (that is, having at least one character after the question mark in the url) such as calling domain.com/request.php?a will yield:
object(request)#1 (1) { ["Get":"request":private]=> array(1) { ["menu"]=> NULL } }
How can I force filter_input_array() to return an array so that default values will be built even if I call an url with no $_GET value defined like index.php?
It seems possible to rewrite a request from .htaccess so that I could mimic a $_GET value being defined if there are not, but it feels weird.
Why not to use another simple way?
var_dump(filter_var_array($_GET, array(
'key' => FILTER_DEFAULT,
), true));
In Python it is possible to have a function with several variables all having a default value. And then just passing the value of one of the values. So if I have
function foo(a=10,b=50, c=70)
pass
pass
return
Then I can call
foo(b=29)
and it would call
foo(10,29,70)
(using the default for all the values, and the exact value for that one variable).
Is something similar possible in PHP?
No there is no equivalent to that in PHP. You can have default values for function arguments, but they are evaluated from left to right and are not named:
function test($var1 = 'default1', $var2 = 'default2')
{
}
In that example the two variables are optional, but you must specify the first argument if you want to specify the second.
test(); // works
test('arg1'); // works
test('arg1', 'arg2'); // works
test('arg2'); // this will set the first argument, not the second.
A common workaround if you need flexibility on your optional arguments is to pass an array as the argument:
function test($options)
{
}
This can have a variable number of arguments in the form of a single associative array:
$options = array('var1' => 'arg1', 'var2' => 'arg2');
test($options);
Use array as an argument. For example:
function a(array $params) {
$defaults = array(
'a' => 10,
'b' => 50,
'c' => 70,
);
$params += $defaults;
// use $params
}
a(array('b' => 29));
When calling a function is there a way to simplify the argument list? Instead of using $blank.
$subscribe=1;
$database->information($blank,$blank,$blank,$blank,$blank,$blank,$subscribe,$blank,$blank,$blank,$blank,$blank);
function information ($search,$id,$blank,$category,$recent,$comment,$subscribe,$pages,$pending,$profile,$deleted,$reported) {
//code
}
You could pass in an array with the specified keys, and merge it with an array of default values
So instead of
function foo($arg1 = 3, $arg2 = 5, $arg3 = 7) { }
You'd have
function foo($args) {
$defaults = array(
'arg1' => '',
'arg2' => null,
'arg3' => 7
);
// merge passed in array with defaults
$args = array_merge($defaults, $args);
// set variables within local scope
foreach($args as $key => $arg) {
// this is to make sure that only intended arguments are passed
if(isset($defaults[$key])) ${$key} = $arg;
}
// rest of your code
}
Then call it as
foo(array('arg3' => 2));
Yes, pass an array instead, or refactor. A long arguments list is usually a bad smell.
function information(array $params) {....
information(array('search'=>'.....
Twelve arguments are generally too many for one function. It's likely that your code could be simplified (including the argument lists getting shorter) by refactoring function information which looks likely to be a monster.
Stopgap measures you can use in the meantime are
adding default argument values
making the function accept all its arguments as an array
Both of the above will require you to visit all call sites for the function for review and modification.
Adding default arguments is IMHO the poor choice here, as by looking at the example call it seems that you would need to make all arguments default, which in turn means that the compiler will never warn you if you call the function wrongly by mistake.
Converting to an array is more work, but it forces you to rewrite the calls in a way that's not as amenable to accidental errors. The function signature would change to
function information(array $params)
or possibly
function information(array $params = array())
if you want all parameters to be optional. You can supply defaults for the parameters with
function information(array $params) {
$defaults = array('foo' => 'bar', /* ... */);
$params += $defaults; // adds missing values that have defaults to $params;
// does not overwrite existing values
To avoid having to rewrite the function body, you can then use export to pull out these values from the array into the local scope:
export($params); // creates local vars
echo $foo; // will print "bar" unless you have given another value
See all of this in action.
You can make it so the function wil automatically fill the variable with a given value like an empty string:
function information ($subscribe, $search="", $id="", $blank="", $category="", $recent="", $comment="", $pages="", $pending="", $profile="", $deleted="", $reported="") {
//code
}
Yes, there are several ways:
Accept an associative array as a single argument, and pass what you need to that. Throw exceptions if a critical argument is missing.
Place critical arguments at the head of the function definition, and optional ones at the end. Give them a default value so that you don't have to declare them.
Recosinder your function. 12 arguments is much too many for one function. Consider using a class/object, or dividing the work between different functions.
Several ways:
function test($input = "some default value") {
return $input; // returns "some default value"
}
function test($input) {
return $input;
}
test(NULL); // returns NULL
function test() {
foreach(func_get_args() as $arg) {
echo $arg;
}
}
test("one", "two", "three"); // echos: onetwothree
I've written a PHP function that can accept 10 parameters, but only 2 are required. Sometimes, I want to define the eighth parameter, but I don't want to type in empty strings for each of the parameters until I reach the eighth.
One idea I had was to pass an abstracted function with an array of parameters which passes it along to the real function.
Is there a better way to set up the function so I can pass in only the parameters I want?
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, $opt);
}
my_color_func('Hi', 'World');
my_color_func('Hello', 'Universe', 'Green');
You can just set the default value to null.
<?php
function functionName($value, $value2 = null) {
// do stuff
}
In PHP 5.6 and later, argument lists may include the ... token to denote that the function accepts a variable number of arguments. The arguments will be passed into the given variable as an array; for example:
Example Using ... to access variable arguments
<?php
function sum(...$numbers) {
$acc = 0;
foreach ($numbers as $n) {
$acc += $n;
}
return $acc;
}
echo sum(1, 2, 3, 4);
?>
The above example will output:
10
Variable-length argument lists PHP Documentation
NOTE: This is an old answer, for PHP 5.5 and below. PHP 5.6+ supports default arguments
In PHP 5.5 and below, you can achieve this by using one of these 2 methods:
using the func_num_args() and func_get_arg() functions;
using NULL arguments;
How to use
function method_1()
{
$arg1 = (func_num_args() >= 1)? func_get_arg(0): "default_value_for_arg1";
$arg2 = (func_num_args() >= 2)? func_get_arg(1): "default_value_for_arg2";
}
function method_2($arg1 = null, $arg2 = null)
{
$arg1 = $arg1? $arg1: "default_value_for_arg1";
$arg2 = $arg2? $arg2: "default_value_for_arg2";
}
I prefer the second method because it's clean and easy to understand, but sometimes you may need the first method.
Starting with PHP 8 you are able to use named arguments:
function namedParameters($paramOne, $paramTwo, $paramThree = 'test', $paramFour = null)
{
dd($paramOne, $paramTwo, $paramThree, $paramFour);
}
We can now call this function with the required params and only the optinal params, that we want to differ from the default value which we specified in the function.
namedParameters('one', 'two', paramFour: 'four');
Result:
// "one", "two", "test", "four"
I think, you can use objects as params-transportes, too.
$myParam = new stdClass();
$myParam->optParam2 = 'something';
$myParam->optParam8 = 3;
theFunction($myParam);
function theFunction($fparam){
return "I got ".$fparam->optParam8." of ".$fparam->optParam2." received!";
}
Of course, you have to set default values for "optParam8" and "optParam2" in this function, in other case you will get "Notice: Undefined property: stdClass::$optParam2"
If using arrays as function parameters, I like this way to set default values:
function theFunction($fparam){
$default = array(
'opt1' => 'nothing',
'opt2' => 1
);
if(is_array($fparam)){
$fparam = array_merge($default, $fparam);
}else{
$fparam = $default;
}
//now, the default values are overwritten by these passed by $fparam
return "I received ".$fparam['opt1']." and ".$fparam['opt2']."!";
}
If only two values are required to create the object with a valid state, you could simply remove all the other optional arguments and provide setters for them (unless you dont want them to changed at runtime). Then just instantiate the object with the two required arguments and set the others as needed through the setter.
Further reading
Martin Fowler on Constructor vs Setter Injection and
Dependency injection through constructors or property setters?
I know this is an old post, but i was having a problem like the OP and this is what i came up with.
Example of array you could pass. You could re order this if a particular order was required, but for this question this will do what is asked.
$argument_set = array (8 => 'lots', 5 => 'of', 1 => 'data', 2 => 'here');
This is manageable, easy to read and the data extraction points can be added and removed at a moments notice anywhere in coding and still avoid a massive rewrite. I used integer keys to tally with the OP original question but string keys could be used just as easily. In fact for readability I would advise it.
Stick this in an external file for ease
function unknown_number_arguments($argument_set) {
foreach ($argument_set as $key => $value) {
# create a switch with all the cases you need. as you loop the array
# keys only your submitted $keys values will be found with the switch.
switch ($key) {
case 1:
# do stuff with $value
break;
case 2:
# do stuff with $value;
break;
case 3:
# key 3 omitted, this wont execute
break;
case 5:
# do stuff with $value;
break;
case 8:
# do stuff with $value;
break;
default:
# no match from the array, do error logging?
break;
}
}
return;
}
put this at the start if the file.
$argument_set = array();
Just use these to assign the next piece of data use numbering/naming according to where the data is coming from.
$argument_set[1][] = $some_variable;
And finally pass the array
unknown_number_arguments($argument_set);
function yourFunction($var1, $var2, $optional = Null){
... code
}
You can make a regular function and then add your optional variables by giving them a default Null value.
A Null is still a value, if you don't call the function with a value for that variable, it won't be empty so no error.
As of PHP 7.1.0, type declarations can be marked nullable by prefixing the type name with a question mark (?). This signifies that the value can be of the specified type or null
<?php
function name(?string $varname){
echo is_null($varname);
}
name();
name('hey');
?>
for more info: Click here
If you are commonly just passing in the 8th value, you can reorder your parameters so it is first. You only need to specify parameters up until the last one you want to set.
If you are using different values, you have 2 options.
One would be to create a set of wrapper functions that take different parameters and set the defaults on the others. This is useful if you only use a few combinations, but can get very messy quickly.
The other option is to pass an array where the keys are the names of the parameters. You can then just check if there is a value in the array with a key, and if not use the default. But again, this can get messy and add a lot of extra code if you have a lot of parameters.
PHP allows default arguments (link). In your case, you could define all the parameters from 3 to 8 as NULL or as an empty string "" depending on your function code. In this way, you can call the function only using the first two parameters.
For example:
<?php
function yourFunction($arg1, $arg2, $arg3=NULL, $arg4=NULL, $arg5=NULL, $arg6=NULL, $arg7=NULL, $arg8=NULL){
echo $arg1;
echo $arg2;
if(isset($arg3)){echo $arg3;}
# other similar statements for $arg4, ...., $arg5
if(isset($arg8)){echo $arg8;}
}
Just set Null to ignore parameters that you don't want to use and then set the parameter needed according to the position.
function myFunc($p1,$p2,$p3=Null,$p4=Null,$p5=Null,$p6=Null,$p7=Null,$p8=Null){
for ($i=1; $i<9; $i++){
$varName = "p$i";
if (isset($$varName)){
echo $varName." = ".$$varName."<br>\n";
}
}
}
myFunc( "1", "2", Null, Null, Null, Null, Null, "eight" );
func( "1", "2", default, default, default, default, default, "eight" );