I'm trying to get this to work, but I think the syntax is off.
How do you call a variable as a value within the array?
<?php
$password = "password1";
$USERS["username"] = "".$password."";
//would like the outcome to be: $USERS["username"] = "password1"
?>
To assign a variable to an array index, simply write:
$USERS["username"] = $password;
You should also read up this tutorial, its very useful and its explained very clearly. Good for your future reference. PHP-Arrays
Related
I'm trying to work out how to get values from one of three arrays based on the array name.
$ABC001 = array('A'=>'10','B'=>'2','C'=>'1.0');
$ABC002 = array('A'=>'20','B'=>'4','C'=>'1.1');
$ABC003 = array('A'=>'30','B'=>'6','C'=>'1.2');
I have a variable passed to my script it will be contain something like ABC#001 or ABC#002
I'm removing the # so the var value now matches the array name/
$test = str_replace('#','',$var);
If I do var_dump ( $$test ) I get all the values from the correct array, but if I do echo $$test['A'] or echo $$test[0] I don't get the value from the first key in the correct array.
Can someone advise how to do this.
Thanks
try this ${$test} to get the values of the array
<?php
$ABC001 = array('A'=>'10','B'=>'2','C'=>'1.0');
$ABC002 = array('A'=>'20','B'=>'4','C'=>'1.1');
$ABC003 = array('A'=>'30','B'=>'6','C'=>'1.2');
$var = "ABC#002";
$test = str_replace('#','',$var);
var_dump(${$test}['A']);
In order to use variable variables with arrays, you have to resolve an ambiguity problem. That is, if you write $$test['A'] then the parser needs to know if you meant to use $test['A'] as a variable, The syntax for resolving this ambiguity is: ${$test}['A'] . Please check the documention here PHP Variable Variable
I have a file named questions.php with an array as follows :
$question12 = array("Which is the tallest mountain","Mt Everest");
I am including this file in another file as follows :
require_once('questions.php');
$var = 12;
$question = '$question'.$var.'[0]';
echo $question;
The above code just outputs the following string (not the contents of the variable):
$question12[0]
But I want the variable $question to contain the string present in $question12[0].
How do I accomplish this?
Variable variable is not recommended, but the answer is below:
$question = ${'question'.$var}[0];
You're looking for variable variables.
$id = 12;
$q = "question{$id}";
$q = $$q[0];
You should seriously consider looking into multidimensional arrays to stop having multiple arrays.
Just use $question12[0]. It will give you the desired output.
Using the $var you can do it like this:-
$question = ${'question'. $var}[index];
Sorry, im going to get some hate for mentioning something evil but still it is one of the options
<?php
$question12 = array("Which is the tallest mountain","Mt Everest");
$var = 12;
$question = '$question'.$var.'[0]';
eval("echo $question;");
?>
P.S: eval() is that evil
Imagine this code:
$array1 = "20";
$array2 = "40";
$array3 = "";
$arraydate = array($array1,$array2,$array3); //In this case would be array("20","40","0")
So what I want is that when there is a variable that is null, 0 or empty, then do not make part of the array. The solution to this is to pass from:
array("20","40","0")
to:
array("20","40")
Is there anyway to do this? Sorry for my bad english. Thank you :D.
Use $arraydate = array_filter($arraydate);
According to the manual, if no callback is given, it will remove all items that equal to false.
Have you actually looked in the PHP Manual? They provide a one line solution with array_filter...
$newAray = array_filter($arraydate);
Wrong Imagination this would never result to array("20","40","0"), it would be instead
array ( "20", "40", "")
And even of you are getting that then use array_filter function to filter value
This seem so simple, and yet I can't find a solution anywhere.
What I want to do is add the contents (r-value) of a variable to an associative array instead of a reference to the variable.
For example, I want this:
$myStr1 = "sometext";
$myStr2 = "someothertext";
$myArray = array(
"key1"=>$myStr1,
"key2"=>$myStr2
);
echo($myArray["key1"]);
To produce this:
"sometext"
Instead of this:
"1" // why??
Any help would be appreciated.
EDIT:
The above works; my bad. Here's the real problem - my $myStr1 variable isn't just assiged a string literal like in the above; it's created using the following syntax:
$myStr1 = "sometext" + anObject->intProperty + "moretext";
Basically I use the + to concatenate various types into a string. Maybe + isn't doing what I think it's doing?
EDIT:
It was definitely the + operator. I casted all non-strings to strings and used . to concatenate instead.
You've got it correct the first time. Try this:
$myStr1 = "sometext";
$myStr2 = "someothertext";
$myArray = array(
"key1"=>$myStr1,
"key2"=>$myStr2
);
unset($myStr1);
echo($myArray["key1"]);
Even though we unset() the $myStr1 variable, it still echoed sometext.
It should be noted that while it is possible to set $myStr1 by reference, it's not the default.
Try your code and its result is:
sometext
I tried to find a proper and explanatory title but I couldn't and I will try to explain what I am asking here:
Normally if you don't assign an empty array to a variable, you can start assign values to indexes like this:
$hello["world"] = "Hello World";
...
echo $hello["world"];
but I always encounter such definition:
$hello = array() //assigning an empty array first
$hello["hello"] = "World";
...
echo $hello["hello"];
Why is it used a lot. Is there a performance gain or something with the second one?
Thanks.
Two reasons:
Better readability (you know the array is initialized at this point)
Security - when running on a system with register_globals enabled a user could add e.g. hello[moo]=something to the query string and the array would already be initialized with this. $hello = array(); overwrites this value though since a new array is created.
Initializing your variables is good practice.
Take for example this:
$foo = 'bar';
// 10 lines and 1 year later
$foo['baz'] = 'test';
Congratulations, you now have the string "tar".
This may happen accidentally and introduce needless bugs. It gets even worse with conditional variable creation. It's avoided easily by getting into the good habit of explicitly initializing your variables.
$hello = array();
if(someConditionIsTrue){
$hello["world"] = "Hello World";
}
foreach($hello as $val){ // this will not give you any error or warning.
echo $val;
}
But
if(someConditionIsTrue){
$hello["world"] = "Hello World";
}
foreach($hello as $val){ // this will give you error .
echo $val;
}
If I remember correctly, the first one will produce a warning by PHP if you have error_reporting as E_ALL. You should always use the second method because it explicitly initialises a new array. If you are looking through code and out of nowhere see $hello["hello"] but cannot recall seeing any reference to $hello before, it would be confusing.
The same will happen if you do $hello[] = "World", a warning will be displayed