How to delete a piece of data from an array in php

In PHP development, array (Array) is a very common data type, which can be used to store multiple data items, such as numbers, strings, Boolean, etc. Sometimes, when processing array data, we need to delete one of the data items. So, how to delete an item of data in the array in PHP? This article will give you a detailed answer.

Method 1: Use the unset() function to delete array elements

In PHP, use the unset() function to delete specified array elements. The basic syntax is as follows:

unset($array[key]);

Among them, $array represents the array variable of the data item to be deleted, and key represents the index or key name of the data item to be deleted.

When using the unset() function, you need to pay attention to the following points:

1. If the data item to be deleted is an index array (that is, the key name is a number), then delete After the data item, the index in the array is reordered.
2. If the data item to be deleted is an associative array (that is, the key name is a string), the order of the key names of other data items will not change after deleting the data item.

The following is a simple example to illustrate how to use the unset() function to delete a piece of data in the array:

<?php   $fruits = array("apple", "banana", "cherry", "date");
  unset($fruits[1]); // 删除索引为1的数组元素（即“banana”）
  print_r($fruits); // 输出结果为：Array([0] => apple [2] => cherry [3] => date)
?>

In this example, we define a file called $fruits array, which contains four string elements. Next, we use the unset() function to delete the second element (i.e. "banana") in the array, and finally use the print_r() function to output the modified array. In the output, you can see that the element with index 1 no longer exists.

Method 2: Use the array_splice() function to delete array elements

In addition to using the unset() function, you can also use the array_splice() function to delete a piece of data in the array. The array_splice() function can not only delete specified elements, but also insert new elements into the array. The basic syntax is as follows:

array_splice($array, $start, $length, $replacement);

Among them, $array represents the array variable to be operated, $start represents the starting index position to be operated, $length represents the number of data items to be deleted, and $replacement represents the number of data items to be inserted. new element.

When the $length parameter is empty, the array_splice() function will delete elements starting from the $start index to the end of the array. If the $replacement parameter is also passed in, the array_splice() function will also insert new elements at the location of deleted elements.

The following is an example of using the array_splice() function to delete an item of data in an array:

<?php   $fruits = array("apple", "banana", "cherry", "date");
  array_splice($fruits, 1, 1); // 删除索引为1的数组元素（即“banana”）
  print_r($fruits); // 输出结果为：Array([0] => apple [1] => cherry [2] => date)
?>

In this example, we use the array_splice() function to delete the element with index 1 in the $fruits array (i.e. "banana") is deleted, and you can see in the output that the element no longer exists.

Summary

Both of the above two methods can be used to delete a data item in the array. Using the unset() function to delete array elements is easy, but inserting new elements is not supported. Using the array_splice() function can support inserting new elements, but it is a little more troublesome to use. Developers can choose a method that suits them based on specific circumstances.

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