How to remove empty elements from php array

In development, array operations are very common, and sometimes there will be some empty elements in the array. These elements have no practical effect on our development, and may even cause unpredictable errors. Therefore, we need to eliminate empty elements in the array in PHP for better development.

1. What is an empty element?

In a PHP array, an empty element means that an element in the array has no value. In PHP, null values ​​refer to: null, false, empty string, empty array, and 0. Therefore, the following elements are all empty elements:

$emptyArray = [];
$nullValue = null;
$falseValue = false;
$emptyString = '';
$zeroValue = 0;

2. How to remove empty elements

PHP provides many methods to remove empty elements from an array. The following are commonly used methods:

1. Use the array_filter() function

array_filter() is a function provided by PHP that can filter elements in an array and return the filtered array. The following is an example of using the array_filter() function to remove empty elements:

$array = ['foo', null, 'bar', '', 'baz', false, ''];
$array = array_filter($array);
print_r($array);

The output result is:

Array (
    [0] => foo
    [2] => bar
    [4] => baz
)

It can be seen that the processed array has removed empty elements.

2. Use foreach loop to traverse and eliminate empty elements

In addition to using the array_filter() function, we can also use foreach loop to traverse and eliminate empty elements during the traversal process . The following is an example of using foreach loop to eliminate empty elements:

$array = ['foo', null, 'bar', '', 'baz', false, ''];
$newArray = [];
foreach ($array as $value) {
  if (!empty($value)) {
    $newArray[] = $value;
  }
}
print_r($newArray);

The output result is:

Array (
    [0] => foo
    [1] => bar
    [2] => baz
)

Compared with using the array_filter() function, using foreach loop to eliminate empty elements requires more time code, but allows for more flexibility with arrays.

3. Notes

1. If the array contains 0 of string type, after using the array_filter() function to remove it, the 0 of string type will also be regarded as empty. elements and therefore require special attention.
2. If the array contains array elements, using the array_filter() function will only remove the empty array, but cannot process the empty elements in the array.
3. For cases containing multiple levels of nested arrays, it will be more troublesome to handle. It is necessary to traverse the array multiple times and process it step by step.

4. Summary

In PHP, removing empty elements from an array is a common requirement. Common methods include using the array_filter() function and foreach loop traversal. When removing empty elements, you need to pay attention to the string type 0 and the situation of multi-level nested arrays. In actual development, we can choose the appropriate method according to the specific situation.

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