How does php determine whether an array is empty?

In PHP, there are many ways to judge whether an empty array has many methods. This article will introduce these methods in detail for you.

Method 1: Use the count () function.

The most common way to judge an empty array is to use the count () function. Determine whether the array is empty by counting the number of elements in the array. The concrete implementation is as follows:

If (count ($ array) = = 0) {/$ array is an empty array} else {// $array is not an empty array}

This method is very simple and can be completed by using only one conditional statement. However, it needs to traverse the whole array to calculate the number of elements, so it may affect performance when dealing with large arrays.

Method 2: Use the empty () function.

The empty () function can determine whether a variable is empty, including empty string, empty array, null and false. The concrete implementation is as follows:

If (empty ($ array)) {/$ array is an empty array} else {// $array is not an empty array}

This method is faster than the count () function because it does not need to traverse the entire array. However, it may also judge the elements containing false, 0 and ""in a non-empty array as empty, so it is not suitable for all cases.

Method 3: Use isset () function.

The isset () function can determine whether a variable exists and is not null. Therefore, if an array variable exists but has no elements, it is not an empty array. The concrete implementation is as follows:

if (isset($array) && ! Empty ($ array)) {/$ array is not an empty array} else {// $array is an empty array}

Note that you need to use both the isset () function and the empty () function, because if you only use the isset () function to judge whether the array is empty, the empty array will also be judged to exist without elements.

Method 4: Use the array () function.

Defining an empty array is also a way to judge whether the array is empty. The concrete implementation is as follows:

If ($ array = = = array ()) {/$ array is an empty array} else {// $array is not an empty array}

This method is very efficient because it does not need to traverse the array. However, it needs to define an extra empty array in the code, which may lead to bloated code.

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