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How to master the replacement of PHP array elements, many novices are not very clear about this, in order to help you solve this problem, the following editor will explain in detail for you, people with this need can come to learn, I hope you can gain something.

In the previous article, we mentioned that we can replace a string in PHP through the str_replace function and the substr_replace () function. Strings and arrays are very important data types in PHP, so how can we replace the elements in the array?

In PHP, you can replace elements in an array through the array_splice function, the array_replace function, and the array_replace_recursive function. Let's take a look at the use of these three functions respectively.

Array_splice function

In PHP, you can use the array_splice function to remove the element from the array and replace it with a new element. The basic syntax format of the array_splice function is as follows:

Array_splice (array,start,length,array)

Among them, it should be noted that:

The first parameter array represents the array we need to operate on, the parameter start is used to indicate the starting position of the deleted element, the parameter length is used to specify the number of elements to be removed, and the length of the array in the result is returned, and the second parameter array is used to specify the array with elements to be inserted into the original array.

When the parameter start is positive, it is removed from the offset specified by that value in the array. If the parameter is negative, it is removed from the offset specified by the reciprocal value at the end of the array. If it is 0, it is removed from the first element.

The parameter length indicates the number of elements removed if it is positive, or removes all elements from start to the reciprocal length at the end of the array if it is negative. If the value of this parameter is not set, it removes all elements from the position set by the start parameter to the end of the array.

The return result of this function is an array of extracted elements.

Let's take a look at the application of the array_splice function through an example, as follows:

Output result:

In the above example, the array elements are replaced by the array_splice function. Let's take a look at the other two methods.

Array_replace function

In PHP, you can use the array_replace function to replace the value of the first array with the value of the following array. The basic syntax format of the array_replace function is as follows:

Array_replace (array1,array2,array3...)

Among them, it should be noted that:

The parameter array1 represents the array that we need to replace, the parameter array2 represents the array that specifies the values to replace array1, and array3 represents the array that specifies multiple arrays to be replaced, and the following values overwrite the previous values. The returned result is the replaced array, and if there is an error in the function, the returned result is NULL.

Let's take a look at the use of the array_replace function through an example, as follows:

Output result:

In the above example, a key name exists not only in the first array, but also in the second array, so the value in the first array will be replaced by the value in the second array. If the key name in the first array is separate, there is no such key name in the other array, so the key name and the value will remain the same.

This is a case where a key exists only in the first array. Let's see that a key exists only in the second or subsequent array. Let's look at another example:

Output result:

As can be seen in the above example, when a key does not exist in the first array, but only exists in the second array, the key name and value will be recreated in the first array. The above examples are two arrays. Let's take a look at three arrays.

Examples are as follows:

Output result:

In the above example, three arrays appear, and it is important to note that the values of the subsequent arrays override the values of the previous array.

This is the basic usage of the array_replace function, so let's move on to the usage of the array_replace_recursive function.

Array_replace_recursive function

In PHP, you can use the array_replace_recursive function to recursively replace the value of the second array with the value of the second array.

The basic syntax format of the array_replace_recursive function is as follows:

Array_replace_recursive (array1,array2,array3...)

Among them, it should be noted that:

The parameter array1 represents the array that we need to replace, the parameter array2 represents the array that specifies the values to replace array1, and array3 represents the array that specifies multiple arrays to be replaced, and the following values overwrite the previous values. The returned result is the replaced array, and if there is an error in the function, the returned result is NULL.

If the array does not use the specified key to specify the elements in the array, then the array_replace_recursive function can be treated as an array_replace function.

If a key exists in both the first array and the second array, the value of the second array replaces the value of the first array, and if a key exists only in the first array, the value is saved. If a key exists only in the second array, the same element is created in the first array.

Let's take a look at the use of array_replace_recursive through an example, as follows:

Output result:

In the above example, the values following multiple arrays overwrite the previous values.

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