How to determine whether an array is empty in php (4 methods)

In PHP development, we often need to perform judgment operations on arrays. One of the common judgments is to judge whether the array is empty. Especially in web development, we need to frequently receive and process data submitted by users. At this time, it is particularly important to determine whether the array is empty. This article will introduce several PHP methods to determine if an array is not empty.

1. Use the count() function

The count() function is a built-in function in PHP used to count the number of array elements. Using this, we can easily determine whether the array is empty. When the array is empty, the count() function returns a value of 0. We can use this feature to make judgments. The code example is as follows:

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

2. Use empty() function

empty() function is a built-in function in PHP used to determine whether a variable is empty. The empty() function returns true when the variable is empty, false otherwise. We can also use this function to make judgments. When judging an array, if we use the empty() function, we need to pass the array variable as a parameter to the function. The sample code is as follows:

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

3. Use the !empty() function

The functions of the empty() function are opposite. The !empty() function is used to determine whether the variable is non-empty. The !empty() function returns true when the variable is non-empty, false otherwise. Therefore, we can also use this function to determine whether the array is non-empty. The code example is as follows:

$arr = array();
if (!empty($arr)) {
    echo '数组不为空';
} else {
    echo '数组为空';
}

4. Use the isset() function

The isset() function in PHP is used to detect whether the variable has been declared and assigned a value. When determining whether the array is non-empty, we can pass the array variable as a parameter to the isset() function. If the variable has been declared and assigned a value, the isset() function returns true, otherwise it returns false. The code example is as follows:

$arr = array();
if (isset($arr) && count($arr) > 0) {
    echo '数组不为空';
} else {
    echo '数组为空';
}

Summary

Through the above example code, we can see that it is very easy to determine that an array is not empty in PHP. We can use PHP built-in functions count(), empty(), !empty() and isset() to determine whether an array is empty or non-empty. In actual development, we can choose the appropriate function to operate according to specific needs. However, it should be noted that when using the empty() and isset() functions, these two functions can correctly determine whether the array is empty or non-empty only after the array variable has been declared and assigned a value.

In short, arrays are one of the most commonly used data types in PHP, and the judgment and operation of arrays are an indispensable part of development. Through these methods introduced in this article, readers can quickly determine whether the array is empty and avoid unnecessary errors in the program.

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