How to remove element from php array?
Jul 02, 2025 pm 04:41 PM
There are three ways to delete array elements in PHP: use unset() to delete elements of the specified key, use array_diff() to delete specific values, and use array_filter() to filter by condition. 1. unset($array[key]) directly deletes elements of the specified key, but does not reset the index; 2. array_diff($array, [values]) deletes one or more specified values, and returns a new array and needs to be reassigned; 3. array_filter($array, callback) filters retained elements according to callback function conditions, which is suitable for complex logic. Note: If continuous indexes are required after unset(), it should be used with array_values(). Unset() is usually the fastest when processing large arrays.
In PHP, if you want to delete an element from an array, there are actually several ways to do this, depending on whether you want to delete a value or a key, and whether you need to keep the index. Let’s talk about some common and practical methods below.
Use unset() to delete elements of the specified key
This is the most straightforward way to do that you know the key name or index of the element you want to delete.
$array = [10, 20, 30, 40]; unset($array[2]);
After execution, the element (that is, 30) of index 2 will be deleted. Note: unset() will not re-index the array. If you want the array to remain continuously indexed, you need to use array_values() to process it later.
Applicable scenarios:
- Delete elements in a specific location
- Delete a key-value pair in the associative array
Use array_diff() to delete elements of a specific value
If you only know the value you want to delete, not the key, you can use array_diff() . This function compares the array and returns the difference set.
$array = [10, 20, 30, 40]; $array = array_diff($array, [30]);
This way, the element with a value of 30 is deleted. However, be aware that array_diff() returns a new array, and the original array will not be modified, so we usually reassign the result to the original array.
Features:
- Multiple specified values ??can be deleted at once
- No other element's key names will be affected
Use array_filter() to filter elements by condition
If your deletion logic is more complicated, such as determining which elements should be deleted based on certain rules, array_filter() will come in handy.
$array = [10, 15, 20, 25];
$array = array_filter($array, function($value) {
return $value <= 18;
});This code will retain all elements less than or equal to 18, and the rest will be filtered out. You can customize the judgment logic in the callback function.
Advantages:
- Flexible, suitable for complex filtering conditions
- No specific keys or values ??are logically controllable
Small details reminder
- If you want the array index to be continuous after using
unset(), remember to add$array = array_values($array); - When deleting elements, if the array is a reference pass or a nested structure, you need to pay attention to the impact of scope and structure changes.
- Performance differences may appear when processing large arrays, and generally
unset()is the fastest
Basically these are the methods. Choosing the appropriate method in different scenarios is not complicated but it is easy to ignore some small details, such as index rearrangement or value type matching issues.
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