How to determine if an array is empty in php

In PHP, there are many ways to determine whether an array is empty.

1. Use the count function

The count function can return the number of elements in an array. When the array is empty, the return value is 0.

$arr = [];
if (count($arr) == 0) {
    echo "数组为空";
}

2. Use the empty function

The empty function can check whether a value is empty. When checking an empty array, the return value is true.

$arr = [];
if (empty($arr)) {
    echo "数组为空";
}

It should be noted that when the value of an element in an array is 0, the empty function will also return true, so it should be used with caution when judging a non-empty array.

3. Use the ! operator

You can use the ! operator to determine whether an array is empty. When the array is not empty, the return value is true.

$arr = [];
if (!$arr) {
    echo "数组为空";
}

It should be noted that when there are false values ​​such as false, null, empty string, etc. in the array, this judgment method may cause misjudgment.

4. Use the is_array function

The is_array function can determine whether a value is an array type. When a value is not an array type, the return value is false. Therefore, when you need to determine whether a variable is an empty array, you can first use the is_array function to check whether the variable is an array type, and then use the corresponding method to determine.

$arr = [];
if (is_array($arr) && count($arr) == 0) {
    echo "数组为空";
}

To sum up, you can use the count function, empty function, ! operator and is_array function to determine whether an array is empty. In practical applications, it is necessary to choose an appropriate method according to the specific situation to ensure the accuracy and reliability of the judgment.

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