CODEWITHSUNDEEP
phpvariablesargumentsglobal
Rob
Rob

Reputation: 939

Passing global variables and arguments to a function in PHP

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 :)

Upvotes: 2

Views: 1853

Answers (4)

kaiser
kaiser

Reputation: 22333

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.

Upvotes: 0

Sean Thayne
Sean Thayne

Reputation: 883

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");

Upvotes: 0

Pramendra Gupta
Pramendra Gupta

Reputation: 14873

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);

Upvotes: 1

stewe
stewe

Reputation: 42622

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.

Upvotes: 3

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