php - unset variable from variable array with for loop

Question

i want to create a for loop in order to unset the spesific variables in an array. i cant find any answer on the internet. here is my code.

$randomnumber=242;
$variables= array('var','var2','randomnumber');
for ($i = 0; $i < count($variables); $i++) {
unset($variables[$i]);
}

echo $randomnumber;

output is:

i dont know what am i missing. please help me guys. i want to unset "var1", "var2", and "randomnumber" variables in the array of "variables". output should be "undefined variable : $randomnumber" or smth like that.

Why should it? $randomnumber is not used anywhere in your for loop code... — Rizier123
– Rizier123, Commented Jan 8, 2017 at 17:11
Then just do unset($randomnumber); your array and for loop have nothing to do with your $randomnumber variable — Rizier123
– Rizier123, Commented Jan 8, 2017 at 17:13
on third for loop it should work like "unset($variables[3])" > "unset($randomnumber)" — DoMajor7th
– DoMajor7th, Commented Jan 8, 2017 at 17:14
if you have 600 variables to unset, you want to use a for loop :) — DoMajor7th
– DoMajor7th, Commented Jan 8, 2017 at 17:14

u_mulder · Accepted Answer · 2017-01-08 17:12:57Z

2

Code

unset($variables[$i]);

means

unset value with key $i from array $variables

If you want to unset a variable with name $variables[$i] then you should use variable variable:

$randomnumber=242;
$variables= array('var','var2','randomnumber');
for ($i = 0; $i < count($variables); $i++) {

    // variable variable syntax here
    unset(${$variables[$i]});

}

echo $randomnumber;

answered Jan 8, 2017 at 17:12

u_mulder

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3 Comments

DoMajor7th Over a year ago

YOU ARE INCREDIBLE. thank you. i was searching for that for a long time!

u_mulder Over a year ago

count is O(1) like taking a value from a variable, isn't it?

Rizier123 Over a year ago

@u_mulder Still you count the array 3 times instead of just once and store the value in an array.

Chris · Accepted Answer · 2017-01-08 19:20:13Z

0

simpler and faster solution:

$randomnumber = 242;
$variables = ['var', 'var2', 'randomnumber'];

foreach ($variables as $variableName) {
    unset($$variableName);
}

answered Jan 8, 2017 at 19:20

Chris

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