PHP deletes array key name and specified key value

In PHP development, array is an essential data structure. However, when dealing with arrays, we often need to delete a specific key or delete the item containing the key value. This article will introduce how to delete a specified key value from an array in PHP.

In PHP, deleting array key values ​​is a very common operation. Sometimes we need to delete the value under a specified key name or delete all items containing the specified value in the entire array. Below we introduce the deletion methods for these two situations respectively.

1. Delete the value under the specified key name

In PHP, deleting the value under the specified key name is very simple. We need to use PHP's unset() function to delete the value corresponding to a certain key name in the array. For example, in the following array, we want to delete the value corresponding to the key name name2:

$array = array(
  'name1' => 'value1',
  'name2' => 'value2',
  'name3' => 'value3'
);

To do this, we can use the unset() function to delete Specify the value under the key name:

unset($array['name2']);

After executing the above code, the $array array will become:

$array = array(
  'name1' => 'value1',
  'name3' => 'value3'
);

Through unset() The function can easily delete the value of a specified key in an array, which is a very common operation in PHP.

2. Delete all items containing the specified value

In PHP, to delete all items containing the specified value, you need to use the language's built-in function: array_filter() Functions and anonymous functions.

array_filter() The function allows us to filter the array and only retain the elements that meet certain conditions. Therefore, if we want to delete all items with a specified value, we only need to filter out all elements that meet the criteria.

Let's look at an example, suppose we have the following array and we need to remove all items with value value2.

$array = array(
  'name1' => 'value1',
  'name2' => 'value2',
  'name3' => 'value2'
);

In order to delete all items with a value of value2, we first need to define an anonymous function. This function will filter all items in the array that do not contain the specified value and return a new array.

The following is the code of the anonymous function:

$needle = 'value2';
$filtered_array = array_filter($array, function ($value) use ($needle) {
    return $value != $needle;
});

In the above code, we first define a $needle variable to store the values ​​that need to be filtered out. Next, we use the array_filter() function, using comparison operators in the anonymous function to exclude all elements containing the $needle variable, and then return a new array composed of the remaining elements.

After running the above code, the $filtered_array array will get the following results:

$array = array(
  'name1' => 'value1'
);

The above code is completed through the array_filter() function and anonymous function In order to delete all items containing the specified value, a suitable array is obtained.

Summary

In PHP, deleting a specified key value in an array is a common operation. We can use the unset() function to easily delete the value corresponding to a specified key name. If we need to delete all items containing a specified value, we need to use the array_filter() function and anonymous function. These two functions can complete related filtering and processing tasks. Hopefully this article will help us handle PHP array related tasks more easily.

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