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How to get the position of a value in an array in php
- PHPzOriginal
- 2023-04-20 15:07:501976browse
In PHP, array is a very useful data type. It allows us to save multiple values together and access these values by index or key. Sometimes we may want to know the position of a certain value in the array. In this case, we need to use the array search function.
In PHP, we can use various methods to find values in an array. Several of these methods will be introduced below.
1. Use the array_search function
The array_search function allows us to find a specific value in an array and return the key name of the first occurrence of the value. If the value does not exist, returns false.
Example:
$arr = array('a', 'b', 'c', 'd');
$key = array_search('b', $arr);
echo $key; // 输出 1
In the above example, we use the array_search function to find the value 'b' in the array $arr and return the key name 1 of the value.
2. Use the array_keys function
The array_keys function can return the key names of all elements in the array with the specified value. If the value does not exist, an empty array is returned.
Example:
$arr = array('a', 'b', 'c', 'd', 'b');
$keys = array_keys($arr, 'b');
print_r($keys); // 输出 Array ( [0] => 1 [1] => 4 )
In the above example, we use the array_keys function to find all elements with a value of 'b' in the array $arr and return their key names.
3. Use the array_values function
The array_values function returns all the values in the array, excluding the key names.
Example:
$arr = array('a', 'b', 'c', 'd');
$values = array_values($arr);
print_r($values); // 输出 Array ( [0] => a [1] => b [2] => c [3] => d )
In the above example, we use the array_values function to return all the values in the array $arr.
4. Use the in_array function
The in_array function is used to find whether a certain value exists in the array. Returns true if present, false otherwise.
Example:
$arr = array('a', 'b', 'c', 'd');
$is_in = in_array('b', $arr);
echo $is_in; // 输出 1
In the above example, we use the in_array function to find whether the value 'b' exists in the array $arr, and it returns true.
Summary:
In PHP, the array search function is very powerful, and we can find specific values in a variety of ways. In actual development, we should choose the appropriate method according to specific scenarios in order to improve the efficiency and readability of the code.
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