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In web development, it is often necessary to query arrays. Sometimes we need to query multiple values in an array. If we search one by one, it will not only be time-consuming and labor-intensive, but also inefficient. And PHP provides an easy way to query multiple values in an array.
First, we need to define an array to be queried, as shown below:
$array = array("red", "blue", "green", "yellow", "white", "black");
Suppose we need to query multiple values in this array, for example, we need to query "red" in the array , "blue" and "black", we can use PHP's array_intersect() function to achieve this.
This function can accept two or more arrays and return a new array containing the elements contained in all arrays.
Let's see how to use the array_intersect() function to query multiple values. We first form multiple values into an array:
$to_query = array("red", "blue", "black");
Then we can use the array_intersect() function to query multiple values in this array:
$result = array_intersect($array, $to_query);
In this way, we can get the multiple values we need to query in the $result array. You can use the print_r() function to output the $result array:
print_r($result);
The output result is as follows:
Array ( [0] => red [1] => blue [5] => black )
As you can see, we have queried the array The three values of "red", "blue" and "black" in . Note that the array index of the output result is the same as the index of the original array.
As mentioned above, the array_intersect() function can accept multiple arrays, so we can also query multiple sets of values at one time.
Let's look at a more complex example. Suppose we have an associative array that contains information about multiple users:
$users = array(
array("name" => "Tom", "age" => 20, "gender" => "M"),
array("name" => "Jack", "age" => 22, "gender" => "M"),
array("name" => "Mary", "age" => 21, "gender" => "F"),
array("name" => "Lucy", "age" => 19, "gender" => "F")
);
Now, we need to query the information about users whose age is 19 or 22 years old and whose gender is male. We can form an associative array with the conditions to be queried:
$to_query = array("age" => array(19, 22), "gender" => "M");
The first element in this array is an array, including two age values to be queried; the second element is the gender to be queried value.
Then you can use the array_intersect() function to query:
function array_query($array, $to_query) {
return array_filter($array, function ($item) use ($to_query) {
foreach ($to_query as $key => $value) {
if (!in_array($item[$key], (array)$value)) {
return false;
}
}
return true;
});
}
$result = array_query($users, $to_query);
We have customized a array_query() function here. This function accepts two parameters, the first parameter is the array to be queried, and the second parameter is the condition to be queried.
The function internally uses PHP's array_filter() function and anonymous function to filter the array. For the input query condition $to_query, the function first filters the array elements that meet the condition based on this condition.
Then, return the result to the query result $result.
Finally, we can use the print_r() function to output the query results:
print_r($result);
The output results are as follows:
Array ( [0] => Array ( [name] => Tom [age] => 20 [gender] => M ) [1] => Array ( [name] => Jack [age] => 22 [gender] => M ) )
As you can see, we succeeded Two user information that meets the conditions were queried.
In actual development, we often need to perform multi-value queries on arrays. This function can be easily implemented using the array_intersect() function in PHP. In addition, we can also further encapsulate it according to our needs and build functions that suit our own needs.
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