How to determine if a variable is an array in php

PHP is an advanced dynamic scripting language ideal for web development. In PHP, it is often necessary to determine whether a variable is of array type. Although PHP is a loosely typed language, there are situations where we need to ensure that a variable is an array. This article will introduce you how to use PHP to determine whether a variable is an array.

1. Use the is_array function

PHP provides an is_array() function, which is used to determine whether a variable is an array. The syntax of the is_array() function is as follows:

bool is_array (mixed $var)

Among them, $var is the variable that needs to be judged. This function returns true if $var is an array, false otherwise.

Sample code:

$arr = array('first', 'second', 'third', 'fourth');
if (is_array($arr)) {
  echo '$arr is an array';
} else {
  echo '$arr is not an array';
}

The output result is: $arr is an array.

2. Use the gettype function

The gettype() function is used to obtain the type of a variable. If the variable is an array, the function returns "array". You can use this function to determine whether a variable is of array type.

Sample code:

$arr = array('first', 'second', 'third', 'fourth');
if (gettype($arr) == 'array') {
  echo '$arr is an array';
} else {
  echo '$arr is not an array';
}

The output result is: $arr is an array.

3. Use type casting

In PHP, you can use type casting to force a variable to an array type. If a variable cannot be coerced to an array, PHP will automatically convert it to an empty array. Therefore, you can use the following method to determine whether a variable is an array.

Sample code:

$arr = array('first', 'second', 'third', 'fourth');
$var = (array) $arr;
if (count($var) == count($arr)) {
  echo '$arr is an array';
} else {
  echo '$arr is not an array';
}

The output result is: $arr is an array.

4. Use the count function

The count() function is used to count the number of elements in the array. If a variable is not an array, this function returns 0. Therefore, you can use this function to determine whether a variable is an array.

Sample code:

$keyValue = array('one' => 1, 'two' => 2, 'three' => 3);
if (count($keyValue) > 0) {
  echo '$keyValue is an array';
} else {
  echo '$keyValue is not an array';
}

The output result is: $keyValue is an array.

Summary

This article introduces 4 ways to determine whether a variable is an array in PHP. They use the is_array function, gettype function, type cast and count function respectively. These methods can effectively determine the variable type. Just choose one of them according to your specific needs.

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