I'm trying to use $variable inside my callback function. I pass it to another function like this: functionName("egTraders_ItemDataBound"), inside that function I assign it to a variable and the call it like this: $theAssignedFunctionVariable($this, $rowToAdd);
And the function egTraders_ItemDataBound gets called properly but the variable $variable
is undefined. What can I do?
<?php
$variable = "var";
function egTraders_ItemDataBound($sender, $param1) {
echo $variable;
}
?>
If You are running PHP 5.3+ You can achive this by simply creating anonymous functioin with use keyword ( documentation ) :
$bar = 'bar';
$f = function() use ($bar)
{
var_dump($bar);
};
function bar( $fName )
{
$fName();
}
bar($f);
You could pass it in as a param or you could use it as a global in the function. I do not recommend the latter. You should stay away from globals.
Edit for example
$variable = "var";
function egTraders_ItemDataBound($sender, $param1) {
global $variable;
echo $variable;
}
egTraders_ItemDataBound(NULL, NULL);
you need to declare the variable as global because it is out of scope
$variable = "var";
function egTraders_ItemDataBound($sender, $param1) {
global $variable;
echo $variable;
}
The variable is declared outside of the scope of the function. You should revisit your design. I strongly recommend against using global variables as that is poor practice.
Related
I have file a.php that looks like
function func_1() {
inlude_once(b.php);
$somevar = 'def';
func_2($somevar);
}
and b.php that looks like
$some_global_var = 'abc';
function func_2($var) {
global $some_global_var;
echo $some_global_var.$var;
}
And for some reason I get only def as a result, why func_2 don't see $some_global_var ?
Because you forgot the scope of func_1. So when you include your define this is how your code appears to PHP
function func_1() {
$some_global_var = 'abc'; // <- this is inside the scope of the parent function!
function func_2($var) {
global $some_global_var;
echo $some_global_var.$var;
}
$somevar = 'def';
func_2($somevar);
}
You're doing it inside func_1. So the variable was never really available in the global scope. If you defined $some_global_var = 'abc'; outside, then it's in the global scope.
What you should do is inject this as an argument instead. Globals are a bad practice
function func_1() {
$some_global_var = 'abc';
function func_2($var, $var2) {
echo $var2 . $var;
}
$somevar = 'def';
func_2($somevar, $some_global_var);
}
put global in front of it.
per the PHP docs
Using global keyword outside a function is not an error. It can be used if the file is included from inside a function.
you may have an issue with an include file getting in the way
help me get variable in a function within another function
$variable ="alfa";
function foo(){
$variable ="beta";
$my_function = function(){
global $variable;
return $variable;
};
return $my_function();
}
I want the function foo(); print "beta" no "alpha", what's wrong with my code?
print foo(); // this print "alpha" and should print "beta"
Use use instead of global.
$variable ="alfa";
function foo(){
$variable ="beta";
$my_function = function() use ($variable){
return $variable;
};
return $my_function();
}
You can read more about it in docs example #3
You should declare global $variable; before assigning $variable ="beta";.
If not, you are working in the function scope, not global scope.
Try to clear the concept of " Scope of the variables "
inside the function foo() , you declare the variable $variable, Then in the anonymous function you are accessing the $variable you have declared inside the foo(), So if you want to use the global $variable inside the anonymous function, You should make the global $variable right after you declare the function foo()
$variable ="alfa";
function foo(){
global $variable;
$variable ="beta";
$my_function = function(){
global $variable;
return $variable;
};
return $my_function();
}
I have a separate file where I include variables with thier set value.
How can I make these variables global?
Ex. I have the value $myval in the values.php file. In the index.php I call a function which needs the $myval value.
If I add the include(values.php); in the beggining of the index.php file it looses scope inside the function. I will call the same variable in multiple functions in the index.php file.
Inside the function, use the global keyword or access the variable from the $GLOBALS[] array:
function myfunc() {
global $myvar;
}
Or, for better readability: use $GLOBALS[]. This makes it clear that you are accessing something at the global scope.
function myfunc() {
echo $GLOBALS['myvar'];
}
Finally though,
Whenever possible, avoid using the global variable to begin with and pass it instead as a parameter to the function:
function myfunc($myvar) {
echo $myvar . " (in a function)";
}
$myvar = "I'm global!";
myfunc($myvar);
// I'm global! (in a function)
Use inside your function :
global $myval;
PHP - Variable scope
Using the global keyword in the beginning of your function will bring those variables into scope. So for example
$outside_variable = "foo";
function my_function() {
global $outside_variable;
echo $outside_variable;
}
Is there a reason why you can't pass the variable into your function?
myFunction($myVariable)
{
//DO SOMETHING
}
It's a far better idea to pass variables rather than use globals.
Same as if you declared the variable in the same file.
function doSomething($arg1, $arg2) {
global $var1, $var2;
// do stuff here
}
I have two PHP files. In the first I set a cookie based on a $_GET value, and then call a function which then sends this value on to the other file. This is some code which I'm using in join.php:
include('inc/processJoin.php');
setcookie("site_Referral", $_GET['rid'], time()+10000);
$joinProc = new processJoin();
$joinProc->grabReferral($_COOKIE["site_Referral"]);
The other file (processJoin.php) will then send this value (among others) to further files which will process and insert the data into the database.
The problem I'm having is that when the grabReferral() function in processJoin.php is called, the $referralID variable isn't being defined on a global scale - other functions in processJoin.php can't seem to access it to send to other files/processes.
I've tried this in processJoin.php:
grabReferral($rid) {
global $ref_id;
$ref_id = $rid;
}
someOtherFunction() {
sendValue($ref_id);
}
But the someOtherFunction can't seem to access or use the $ref_id value. I've also tried using define() to no avail. What am I doing wrong?
you have to define the global var in the second function as well..
// global scope
$ref_id = 1;
grabReferral($rid){
global $ref_id;
$ref_id = $rid;
}
someOtherFunction(){
global $ref_id;
sendValue($ref_id);
}
felix
personally, I would recommend the $GLOBALS super variable.
function foo(){
$GLOBALS['foobar'] = 'foobar';
}
function bar(){
echo $GLOBALS['foobar'];
}
foo();
bar();
DEMO
This is a simple and working code to initialize global variable from a function :
function doit()
{
$GLOBALS['val'] = 'bar';
}
doit();
echo $val;
Gives the output as :
bar
The following works.
<?php
foo();
bar();
function foo()
{
global $jabberwocky;
$jabberwocky="Jabberwocky<br>";
bar();
}
function bar()
{
global $jabberwocky;
echo $jabberwocky;
}
?>
to produce:
Jabberwocky
Jabberwocky
So it seems that a variable first declared as global inside a function and then initalised inside that function acquires global scope.
The global keyword lets you access a global variable, not create one. Global variables are the ones created in the outermost scope (i.e. not inside a function or class), and are not accessible inside function unless you declare them with global.
Disclaimer: none of this code was tested, but it definitely gets the point across.
Choose a name for the variable you want to be available in the global scope.
Within the function, assign a value to the name index of the $GLOBALS array.
function my_function(){
//...
$GLOBALS['myGlobalVariable'] = 42; //globalize variable
//...
}
Now when you want to access the variable from code running in the global scope, i.e. NOT within a function, you can simply use $ name to access it, without referencing the $GLOBALS array.
<?php
//<global scope>
echo $myGlobalVariable; //outputs "42"
//</global scope>
?>
To access your global variable from a non-global scope such as a function or an object, you have two options:
Access it through the appropriate index of the $GLOBALS array. Ex: $GLOBALS['myGlobalVariable'] This takes a long time to type, especially if you need to use the global variable multiple times in your non-global scope.
A more concise way is to import your global variable into the local scope by using the 'global' statement. After using this statement, you can reference the global variable as though it were a local variable. Changes you make to the variable will be reflected globally.
//<non global scopes>
function a(){
//...
global $myGlobalVariable;
echo $myGlobalVariable; // outputs "42"
//...
}
function b(){
//...
echo $GLOBALS['myGlobalVariable']; // outputs "42"
echo $myGlobalVariable; // outputs "" (nothing)
// ^also generates warning - variable not defined
//...
}
//</non global scopes>
Please use global variables in any language with caution, especially in PHP.
See the following resources for discussion of global variables:
http://chateau-logic.com/content/dangers-global-variables-revisited-because-php
http://c2.com/cgi/wiki?GlobalVariablesAreBad
The visibility of a variable
I hope that helped
<?php
$a = 1;
$b = 2;
function Sum()
{
global $a, $b;
$b = $a + $b;
}
Sum();
echo $b;
?>
I want to declare a global variable using PHP and be used inside functions.
I have tried:
$var = "something";
function foo()
{
echo $var;
}
yet I receive an error stating that the $var is undefined.
How can I solve this?
$var = "something";
function foo()
{
global $var;
echo $var;
}
use the term "global" when you need to use variables that were declared outside your function scope.
PHP variables have function scope. I.e., variables inside a function can't be accessed from outside it and global variables can't (by default) be accessed from inside functions. While using the global keyword inside functions to im-/export variables is a solution, you should not do it. Functions should be self-contained; if you need a value inside a function, pass it as a parameter, if the function needs to modify global values, return them from the function.
Example:
function foo($arg)
{
echo $arg;
}
$var = "something";
foo($var);
Please read: http://php.net/manual/en/language.variables.scope.php