How to determine whether array value is empty in php

In PHP, we can use various methods to determine whether the value of an array is empty. In this article, we will discuss several commonly used methods and provide examples of their use.

Method 1: Use the empty() function to determine whether the array element is empty

The empty() function is a function that comes with PHP and can be used to determine whether the variable is empty, including array elements. . The empty() function returns TRUE when the variable is empty and FALSE otherwise. It is very simple to use this method to determine whether an array element is empty. You only need to pass the array subscript as a parameter to the empty() function.

The following is a simple PHP code example that demonstrates how to use the empty() function to determine whether an array element is empty:

<?php   $arr = array(&#39;value1&#39; => '', 'value2' => 'hello', 'value3' => null, 'value4' => 0);
  if (empty($arr['value1'])) {
      echo "value1 is empty";
  } else {
      echo "value1 is not empty";
  }
?>

In the above code, we create an array containing four An array of elements, and then use the empty() function to determine whether the first element of the array is empty. Since the value of $arr['value1'] is an empty string, the empty() function will return TRUE and we will see the output "value1 is empty".

Method 2: Use the isset() function to determine whether the array element exists and is not empty

isset() function is also a function that comes with PHP to determine whether an array element is empty Before, it is usually necessary to determine whether the element exists. If the array element does not exist, using the empty() function directly will cause PHP to report an error. Therefore, it is a good practice to use the isset() function to determine whether an array element exists, which will return TRUE or FALSE.

The following is a PHP code example that demonstrates how to use the isset() function to determine whether an existing array element is empty:

<?php   $arr = array(&#39;value1&#39; => '', 'value2' => 'hello', 'value3' => null, 'value4' => 0);
  if (isset($arr['value1']) && empty($arr['value1'])) {
      echo "value1 is empty";
  } else {
      echo "value1 is not empty";
  }
?>

In the above code, we use the isset() function to determine whether the array element is empty. Whether the first element exists, if it exists and is empty, "value1 is empty" will be output.

Method 3: Use the array_key_exists() function to determine whether the array element exists and is not empty

Similar to the isset() function, the array_key_exists() function is also used to determine whether there is an element in the original array For the specified key, when executing the empty() function judgment, first use the array_key_exists() function to judge whether the element exists, and if it exists, then judge whether it is empty.

The following is a simple PHP code example that demonstrates how to use the array_key_exists() and empty() functions to determine whether an array element is empty:

<?php   $arr = array(&#39;value1&#39; => '', 'value2' => 'hello', 'value3' => null, 'value4' => 0);
  if (array_key_exists('value1', $arr) && empty($arr['value1'])) {
      echo "value1 is empty";
  } else {
      echo "value1 is not empty";
  }
?>

In the above code, we use array_key_exists( ) function determines whether the first element of the array exists. If it exists and is empty, "value1 is empty" will be output.

Method 4: Use the count() function to determine the number of non-empty elements in the array

The count() function is used to obtain the number of elements in the array. We can combine this function with empty () function is used in combination to determine the number of non-empty elements in the array.

The following is a simple PHP code example that demonstrates how to use the count() and empty() functions to get the number of non-empty elements in an array:

<?php   $arr = array(&#39;value1&#39; => '', 'value2' => 'hello', 'value3' => null, 'value4' => 0);
  $count = count(array_filter($arr));
  if ($count == 0) {
      echo "All values are empty";
  } else {
      echo "There are " . $count . " non-empty values";
  }
?>

In the above code, We use the array_filter() function to remove empty elements in the array, and then use the count() function to get the number of non-empty elements in the array. If the number of non-empty elements is 0, "All values ​​are empty" will be output; otherwise, "There are X non-empty values" will be output, where X represents the number of non-empty elements.

Summary

This article introduces several methods in PHP to determine whether an array element is empty. Use the empty() function, isset() function and array_key_exists() function to determine whether the array element is empty or exists without causing PHP to report an error. Use the count() function to get the number of non-empty elements in the array. When writing PHP code, please choose an appropriate method and judge based on actual needs.

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