How to add key position to php array

In PHP programming, an array is a commonly used data structure that can be used to store a set of related values. In some cases, we may need to add key locations to better organize and access the data in the array. This article will explain how to add key positions to an array in PHP.

In PHP, we can use the following three methods to add key positions:

1. Assign a value to the array key position when directly declaring it

In PHP , we can directly assign the key position through [key value => value] when declaring the array. For example:

$arr = [
   "name" => "Tom",
   "age" => 20,
   "gender" => "male"
];

The above code will create an array containing three key-value pairs, namely "name", "age", and "gender". Array elements can be accessed in the following ways:

echo $arr["name"]; // output: Tom
echo $arr["age"]; // output: 20
echo $arr["gender"]; // output: male

2. Add key positions using array assignment

In PHP, we can use array assignment statements to add key positions, i.e. :$array[key] = value. For example:

$arr = [
   "name" => "Tom",
   "age" => 20
];

$arr["gender"] = "male";

print_r($arr);

In the above code, we first created an array containing two key-value pairs, and then added a new key position "gender" by $arr["gender"] = "male" ". The output is:

Array
(
    [name] => Tom
    [age] => 20
    [gender] => male
)

3. Use the array_push() function to add the key position

If we want to add a new element to the end of the array, represented by the numerical key position For the position of this element, you can use PHP's built-in function array_push(). For example:

$arr = [
   "name" => "Tom",
   "age" => 20
];

array_push($arr, "male");

print_r($arr);

In the above code, we first create an array containing two key-value pairs, and then use the array_push() function to add a new element "male" to the end of the array. The output result is:

Array
(
    [name] => Tom
    [age] => 20
    [0] => male
)

It is worth noting that the key positions added using the array_push() function are numeric key positions and are added at the end of the array.

In summary, we can use the above three methods to add key positions to PHP arrays. In actual programming, we choose the most suitable way to add key positions according to our needs.

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