php determines whether array is empty

In PHP, there are many ways to determine whether an array is empty. Common methods are as follows:

1. Use the empty() function

empty( ) function is a function in PHP used to check whether a given variable is empty. You can use it to determine whether an array is empty, as shown below:

$a = array();    // 定义一个空数组
if(empty($a)){
    echo '数组为空';
}else{
    echo '数组不为空';
}

2. Use the count() function

The count() function is a function in PHP used to return the number of array elements. You can use it to determine whether an array is empty, as shown below:

$a = array();    // 定义一个空数组
if(count($a) == 0){
    echo '数组为空';
}else{
    echo '数组不为空';
}

3. Use isset () function

isset() function is a function used to determine whether a variable exists. You can use it to determine whether an array is empty, as shown below:

$a = array();    // 定义一个空数组
if(isset($a[0])){
    echo '数组不为空';
}else{
    echo '数组为空';
}

Note Point: This method can only determine whether the first element of the array exists. If there are other elements in the array, you still need to use other methods to determine.

4. Use array_key_exists() function

array_key_exists() function is to determine whether the specified key name exists in the array. You can use it to determine whether an array is empty, as follows Shown:

$a = array();    // 定义一个空数组
if(!array_key_exists(0, $a)){
    echo '数组为空';
}else{
    echo '数组不为空';
}

Note: This method can only determine whether there is an element with the key name 0 in the array. If there are other key names in the array, you still need to use other methods to determine.

To sum up, the above are some common methods in PHP to determine whether an array is empty, which can be selected according to specific needs.

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