How to add new elements to php array

In PHP, an array is a very common data structure used to store a set of data. Adding new elements to an array is a basic operation. This article will introduce some methods to achieve it.

1. Use the assignment operator
The most basic method is to use the assignment operator "=" to assign the new element to the subscript of the array. For example, $arr[2] = "new element"; the assignment operator will add a new element to an existing array. If the subscript does not exist, the subscript will be automatically created.

2. Use the subscript as null
Another method is to use the subscript as null to add new elements. When the array does not have any subscript set, new elements can be added when the subscript is null. For example, $arr[] = "new element"; this will add a new element to the end of the array.

3. Use the array_push() function
The array_push() function is a method in PHP used to add one or more elements to the end of an array. For example, array_push($arr, "new element"); this adds a new element to the end of the array. This method can add multiple new elements by adding them to the function one after another.

4. Use the array_unshift() function
The array_unshift() function is similar to the array_push() function, but inserts new elements into the beginning of the array. For example, array_unshift($arr, "new element"); this adds a new element to the beginning of the array. Likewise, this method can also add multiple new elements.

5. Use the " " operator
The " " operator in PHP can connect two arrays together. For example, $arr1 = array("element1", "element2"); $arr2 = array("new element"); $arr = $arr1 $arr2; This will add the new element in the $arr2 array to the $arr1 array the end of.

Summary
This article introduces some common methods of adding new elements to PHP arrays. Each method has its own characteristics and uses, choose according to the actual situation. No matter which method you choose, remember to pay attention to the uniqueness of the key value when adding new elements to avoid duplicate subscripts.

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