PHP query array subscript

PHP is a scripting language commonly used for web development. In PHP, array is a very important data structure. In development, we often need to query the elements in the array, and also need to obtain the subscript value of the array element. This article will introduce how to query the subscript in an array in PHP.

First, let's take a look at how to define an array in PHP:

$array = array("apple", "banana", "orange");

This is a basic array definition, which contains three elements. In PHP, elements in an array can be accessed through numbers or strings as subscript values.

If we want to know the subscript value of an element in the array, we can use the array_search() function in PHP. This function can return the subscript value of the specified value in the array, or false if the value cannot be found.

The following is the syntax of the array_search() function:

array_search(value, array, strict)

Among them, the value parameter is the value to be found, arrayThe parameter is the array to be searched, and the strict parameter indicates whether to perform strict comparison. By default, the strict parameter is false, indicating that weak type comparison is used when comparing. If the strict parameter is set to true, strict comparison is used.

The following is an example of using the array_search() function to query the subscript in an array:

$array = array("apple", "banana", "orange");
$index = array_search("banana", $array);
echo $index; // 输出 1

In the above code, we first define an array. Then, we call the array_search() function and pass in the element and array to be found. array_search()The function returns the index of the element in the array, which we store in the variable $index. Finally, we use the echo command to output the value.

In the above code, the array_search() function returns the subscript value 1 of the element in the array. This is because "banana" is at the second element position in the array, and the array subscript starts from 0, so the subscript value of this element is 1.

If you want to find the subscript values ​​of multiple elements in an array, we can use the array_keys() function. array_keys()The function can return all subscripts of the specified value in the array.

The following is the syntax of the array_keys() function:

array_keys(array, value, strict)

Among them, the array parameter is the array to be found, valueThe parameter is the value to be found, and the strict parameter indicates whether to perform strict comparison. By default, the strict parameter is false, indicating that weak type comparison is used when comparing. If the strict parameter is set to true, strict comparison is used.

The following is an example of using the array_keys() function to query the subscript in an array:

$array = array("apple", "banana", "orange");
$keys = array_keys($array, "orange");
print_r($keys); // 输出 Array ( [0] => 2 )

In the above code, we first define an array. Then, we call the array_keys() function and pass in the element and array to be found. array_keys()The function returns all the subscripts of the element in the array, which we store in the variable $keys. Finally, we use the print_r() command to output the value.

In the above code, the array_keys() function returns the subscript value 2 of the element "orange" in the array, which is stored in an array containing a single element. If you want to query the subscript values ​​of multiple elements in an array, just use the element you want to query as the array of value parameters.

In this article, we introduced how to query the subscript in an array in PHP. We used the array_search() function to query the subscript of a single element in the array, and the array_keys() function to query the subscripts of multiple elements in the array. These functions are very commonly used and can help us quickly find and operate PHP arrays during development.

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