Passing global variables and arguments to a function in PHP - php

Question

Hello and thanks for being there,
I would like to pass a variable ($user) from a previous function to another one, but I need to use the arguments of the new function to pass the values that will render this new one.
Is there any way I can pass a variable from another function to a new function that only expects three arguments, and none of them is the variable from the previous function?
Example:
function my_function($country, $age, $colour) {
if ($user = true) {
echo "User is from " . $country . " and " . $age . " and his favourite colour is " . $colour;
}
}
my_function("italy", 19, "red");
It works if I put inside function my_function:
global $user;
but I believe using global variables is not a good practice.
Any idea on how to pass it as an argument? Should I just add it as another variable after $colour in the arguments of the new function?
Thanks a lot for your help :)

Answer 1

You can pass it as an argument, or better do this:
if ($user) my_function("italy", 19, "red");
since you don't have to use the $user variable inside that function.

Answer 2

You can use this function but best practice will be using class.
i .e if you call my_function("italy", 19, "red"), $user will be false by default
function my_function($country, $age, $colour, $user=false) {
if ($user == true) {
echo "User is from " $country . "and " . $age . " and his favourite colour is " . $colour;
}
}
my_function("italy", 19, "red",true);

Answer 3

Well, global variables are a bad practice, but a viable one in your case.
I would definitely recommend you looking into/using a Object Oriented approached.
There are really a bunch of different ways to achieve what your trying.
One way would be to encapsulate your code into a object.
<?php
class My_Cool_Class {
public $user = false;
public function myFunction($country, $age, $color) {
if ($this->user)
echo "User is from {$country} and {$age} years old and his favourite colour is {$color}";
}
}
$class = new My_Cool_Class();
$class->user = new User();
$class->myFunction("Italy", 19, "red");
Or you could implement a Singleton Pattern to easily get access to your object/functions from anywhere.
<?php
class My_Cool_Class {
public $user = false;
protected static $_instance;
public function getIntance() {
if(!self::$_instance)
self::$_instance = new self();
return self::$_instance;
}
public function setUser($user) {
$this->user = $user;
}
public function myFunction($country, $age, $color) {
if ($this->user)
echo "User is from {$country} and {$age} years old and his favourite colour is {$color}";
}
}
//Set User from anywhere with this
My_Cool_Class::getInstance()->setUser($user);
//Call your function anywhere with this.
My_Cool_Class::getInstance()->myFunction("Italy", 19, "red");

Answer 4

If your previous function is something like this:
/**
* Callback function for so_user_data() that tells if we want to give you info about the user or not.
* #param (string) $user | Accepts a Username as input
* #return (boolean) | true if the User is 'Rob'
*/
function so_user_fn( $user )
{
$allowed_users = array(
'Rob'
,'Jay'
,'Silent Bob'
);
if ( in_array $user, $allowed_users ) )
return true;
// false if not 'Rob'
return false;
}
/**
* Shows the country, age & fav. colour of a user or denies displaying this information
* if the user is not a public v.i.p. or someone other we want to give you info about.
* #uses so_user_fn() | used to determine if the user is 'Rob'
* #param (string) $user | Username
* #param (string) $country | (optional) Country of origin
* #param (integer) $age | (optional) Age of the user
* #param (string) $colour | (optional) Fav. Colour
*/
function so_user_data( $user, $country = 'an unknown country', $age = 'unknown', $colour = 'not known' )
{
$output = "$user is from {$country} and {$age} years old. His favourite colour is {$colour}.";
// Only print the output if the user is 'Rob'
if ( so_user_test( $user ) )
return print $output;
return print 'We are not allowed to give you information about this user.';
}
You can call it like this:
so_user_data( 'Fancy Franzy' );
// outputs: We are not allowed to give you information about this user.
so_user_data( 'Rob' );
// outputs: Rob is from an unknown country and unknown years old. His favourite colour is not known.
so_user_data( 'Silent Bob', 'U.S.A.', '38', 'brown' );
// outputs: Silent Bob is from U.S.A. and 38 years old. His favourite colour is brown.