PHP determines whether it is an empty array

In PHP, in many cases, we need to determine whether an array is empty. Determining whether an array is empty can be implemented in several ways.

Method 1: Use the empty() function

There is a built-in function empty() in PHP, which can determine whether a variable is empty. When judging whether an array is empty, you only need to pass the array name as a parameter to the empty() function, for example:

$arr = array();

if(empty($arr)){
    echo "数组为空";
} else {
    echo "数组不为空";
}

The output result is: the array is empty

If the array is empty There are elements, for example:

$arr = array(1, 2, 3);

if(empty($arr)){
    echo "数组为空";
} else {
    echo "数组不为空";
}

The output result is: the array is not empty

Method 2: Use the count() function

Another way to determine whether the array is empty is Use the count() function. The count() function returns the number of elements in an array.

When judging whether an array is empty, you can judge whether count($arr) is equal to 0. For example:

$arr = array();

if(count($arr) == 0){
    echo "数组为空";
} else {
    echo "数组不为空";
}

The output result is: the array is empty

If there are elements in the array, for example:

$arr = array(1, 2, 3);

if(count($arr) == 0){
    echo "数组为空";
} else {
    echo "数组不为空";
}

The output result is: the array is not empty

Method 3: Use isset() function

isset() function can be used to determine whether the variable is set and not null. When judging whether an array is empty, you can judge whether isset($arr) is true. For example:

$arr = array();

if(isset($arr) && $arr != null){
    echo "数组不为空";
} else {
    echo "数组为空";
}

The output result is: the array is empty

If there are elements in the array, for example:

$arr = array(1, 2, 3);

if(isset($arr) && $arr != null){
    echo "数组不为空";
} else {
    echo "数组为空";
}

The output result is: the array is not empty

In summary, the above three methods can be used to determine whether an array is empty. In actual development, it is recommended to use the empty() function because it is simpler and clearer, and the code is clearer.

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