PHP Variable Variables and Array Index

Question

I think this can be a simple problem for some of you. I've discovered similar questions, but they don't exactly solve my problem.

I've two arrays.

$array_numerals

Array
(
[2] => two
[3] => three
[4] => four
[5] => five
[6] => six
[7] => seven
)

$array_two

Array
(
[0] => $100
[1] => $200
[2] => $300
)

If I use

echo $array_two[0];

it shows the output properly, which is $100, as expected.

what I want to do is to make the "two" and the "[0]" dynamic. the "two" can be replced with "three" or "four" while the "[0]" can be replaced with "[1]" or "[2]".

So if I use

$i = 2;
$j = 0;

echo $array_{$array_numerals[$i]}[$j];

it doesn't work and shows empty value.

Edit: Thank you all for the comments and answers. I must add that $array_two, $array_three, etc. are fixed variables given by another source, so it's not like I can control the initial construction of these arrays. Hence, the answers given by some of you won't work out of the box (not your fault of course, perhaps I didn't clarify enough in the beginning). The answers given by Amadan and LuvnJesus work the best.

What you're trying to do there is impossible the way you are doing it. Instead, you need to use a jagged array, which is an array of arrays. — Richard Theobald
– Richard Theobald, Commented Jan 28, 2016 at 6:01
@amit-shah the expected output for the second code block should be the same as the first code block, which is "$100". — zzzplayer
– zzzplayer, Commented Jan 28, 2016 at 6:02
You can do this using $$var in PHP. Lets you store a variable or array name in a variable. I've used it rarely but it does work. Example shown in answer post. — LuvnJesus
– LuvnJesus, Commented Jan 28, 2016 at 6:15

Amadan · Accepted Answer · 2016-01-28 06:02:47Z

4

echo ${"array_$array_numerals[$i]"}[$j];

But I must warn you that it is a very bad idea to do this. Rather, use another lookup array:

$array = Array(
  0 => Array(
    2 => "$100",
    ...
  ),
  ...
);

echo $array[$i][$j];

answered Jan 28, 2016 at 6:02

Amadan

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Comments

Sanxofon · Accepted Answer · 2016-01-28 05:58:14Z

0

Why not just use:

$array['two'][0]
$array['three'][0]
$array['four'][0]
$array['four'][1]
etc...

answered Jan 28, 2016 at 5:58

Sanxofon

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Comments

JoCoaker · Accepted Answer · 2016-01-28 05:58:51Z

0

Can you just use it like this:

$array_two[0] = $array_two[1];

And do the same thing with the other array.

answered Jan 28, 2016 at 5:58

JoCoaker

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Comments

LuvnJesus · Accepted Answer · 2016-01-28 06:13:32Z

0

First, create the "name" of the array and store it in a variable:

$arrayname = "array_".$array_numerals[$i];

Store the array values into a new array

$newarray = $$arrayname;

Now output whichever elements you wish:

echo $newarray[$j];

Altogether you have:

$arrayname = "array_".$array_numerals[$i];
$newarray = $$arrayname;
echo $newarray[$j];

answered Jan 28, 2016 at 6:13

LuvnJesus

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Comments

Ali · Accepted Answer · 2016-01-28 06:29:54Z

0

You can use PHP's compact function. I have used your array and created result as you need. please check here

answered Jan 28, 2016 at 6:29

Ali

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