Prepend to multidimensional associative array - php

Question

I'm PHP beginner and have a question:
I have a multidimensional associative array:
array(
"X" => array( "x1" => "1", "x2" => "2", "x3" => "3" ),
"Y" => array( "y1" => "1", "y2" => "2", "y3" => "3" ),
"Z" => array( "z1" => "1", "z2" => "2", "z3" => "3" )
)
and need to prepend "" => "" to every element X, Y, Z, so then it will be:
array(
"X" => array( "" => "", "x1" => "1", "x2" => "2", "x3" => "3" ),
"Y" => array( "" => "", "y1" => "1", "y2" => "2", "y3" => "3" ),
"Z" => array( "" => "", "z1" => "1", "z2" => "2", "z3" => "3" )
)
X, Y, Z names are often changed, so I need to get a key name first and then add new value.
I think of using foreach somehow. I'm trying it, but can achieve it.
Thanks

Answer 1

<?php
$temp = array(
"X" => array( "x1" => "1", "x2" => "2", "x3" => "3" ),
"Y" => array( "y1" => "1", "y2" => "2", "y3" => "3" ),
"Z" => array( "z1" => "1", "z2" => "2", "z3" => "3" )
);
$you_array = array();
foreach($temp as $k=>$v){
$v = array_merge([""=>""],$v);
$you_array[$k] = $v;
}
print_r($you_array);
?>

Answer 2

check the following code:
<?php
$temp = array(
"X" => array( "x1" => "1", "x2" => "2", "x3" => "3" ),
"Y" => array( "y1" => "1", "y2" => "2", "y3" => "3" ),
"Z" => array( "z1" => "1", "z2" => "2", "z3" => "3" )
);
$you_array = array();
foreach($temp as $k=>$v){
array_unshift($v, " ");
$you_array[$k] = $v;
}
print_r($you_array);
?>
Out put :
Array (
[X] => Array ( [0] => [x1] => 1 [x2] => 2 [x3] => 3 )
[Y] => Array ( [0] => [y1] => 1 [y2] => 2 [y3] => 3 )
[Z] => Array ( [0] => [z1] => 1 [z2] => 2 [z3] => 3 )
)

Answer 3

You can use array_unshift to add new elements to an array.
As you already mentioned, create a foreach loop and add your new elements to each sub-array:
$new = array("new_key" => "");
foreach ($yourArray as $key => $value)
array_unshift($yourArray[$key], $new);
Be careful: Your new element needs a key value. An empty key (like you mentioned) is not possible. If you just add a new element without a key array("") it will be added with a numerical key (0 => ""). Existing numerical keys will be modified to start counting from zero.

Answer 4

I think this is what you are looking for
[akshay#localhost tmp]$ cat test.php
<?php
$array=array(
"X" => array( "x1" => "1", "x2" => "2", "x3" => "3" ),
"Y" => array( "y1" => "1", "y2" => "2", "y3" => "3" ),
"Z" => array( "z1" => "1", "z2" => "2", "z3" => "3" )
);
// Input
print_r($array);
// & reference
foreach($array as &$sub_array)
{
$sub_array = array(""=>"")+$sub_array;
}
// Output
print_r($array);
?>
Output
[akshay#localhost tmp]$ php test.php
Array
(
[X] => Array
(
[x1] => 1
[x2] => 2
[x3] => 3
)
[Y] => Array
(
[y1] => 1
[y2] => 2
[y3] => 3
)
[Z] => Array
(
[z1] => 1
[z2] => 2
[z3] => 3
)
)
Array
(
[X] => Array
(
[] =>
[x1] => 1
[x2] => 2
[x3] => 3
)
[Y] => Array
(
[] =>
[y1] => 1
[y2] => 2
[y3] => 3
)
[Z] => Array
(
[] =>
[z1] => 1
[z2] => 2
[z3] => 3
)
)