How to define a custom key in PHP arrays? [closed] - php

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I want to define a two dimension array like below:
[40.1][John]
[40.2][Jane]
[40.7][Mary]
[40.10][Sara]
in other words I want to define an array with custom key. Later I need to access to the array values with the custom key. for instance :
echo(myarray[40.2]);
And I need to generate the array dynamically from XML , since the values are coming from a XML file.
The XML file which I want to generate the array from is like below:
<rules>
<rule>
<id>40.1</id>
<regex><![CDATA[/(?:\)\s*when\s*\d+\s*then)/]]></regex>
</rule>
<rule>
<id>40.2</id>
<regex><![CDATA[/(?:"\s*(?:#|--|{))/]]></regex>
</rule>
How should I create the array with above characteristics?

Answer 1

You can do this very easily by creating an associative array
$myarray = array(
"40.1" => "John",
"40.2" => "Jane",
"40.7" => "Mary",
"40.10" => "Sara"
);
Later on you can iterate over this array with a foreach loop
foreach($myarray as $key => $value) {
echo "<p>" . $key . " = " . $value . "</p>";
}
This will output to the screen
40.1 = John
40.2 = Jane
40.7 = Mary
40.10 = Sara
To create a new array and add items to is as easy as doing this
$myarray = array();
$myarray[$newkey] = $newvalue;
For a two dimensional array, you can define them like this
$myarray = array();
$myarray[$key] = array();
$myarray[$key]['John'] = 'some value';
$myarray[$key]['Jane'] = 'another value';
$myarray[$key2] = array();
$myarray[$key2]['Mary']= 'yet another value';
Or as a short cut
$myarray = array(
$key => array(
'John' => 'some value',
'Jane' => 'another value',
),
$key2 = array(
'Mary' => 'yet another value'
)
);

Answer 2

You can do it with associative array key => value.
$arr = array('40.1' => 'John', '40.2' => 'Jane', '40.7' => 'Mary', ...);
echo $arr['40.1']; // will return John
If you think to extend the data in the feature, you can do it with nested arrays
$arr = array(
'40.1' => array('name' => 'John', 'eyes' => 'green');
'40.2' => array('name' => 'Jane', 'eyes' => 'blue');
);
You can access nested array like this:
echo $arr['40.2']['eyes'] // return blue
You can see also PHP documentation about arrays here

Answer 3

Array keys
Notice! Do not use "float" as type for array keys.
<?php
$array = array(
1 => "a",
"1" => "b",
1.5 => "c",
true => "d",
);
var_dump($array);
Output will be:
array(1) {
[1]=>
string(1) "d"
}
Taken from http://www.php.net/manual/en/language.types.array.php.
Two-dimensional arrays
You can create your array like this:
$data = [
'40.2' => [
'John' => [
// and now this is second dimension
]
]
];
Add aditional stuff:
$data['40.2']['John'][] = ; // just append value
// or
$data['40.2']['John']['sex'] = 'Male'; // store it with key
Or if you need to store scalar values, you can define array like this:
$data = [
'40.2' => [
'John' => 'male' // storing scalar values
]
];
Sorry, If I misunderstood your question.