How to perform conditional query array in php

PHP is a popular server-side programming language that can be used to create dynamic web pages. In PHP, array is a powerful data structure that can easily store and process large amounts of data. PHP arrays can contain different types of elements such as strings, numbers, and other arrays. Conditionally querying arrays in PHP is a very useful skill.

Conditional query arrays in PHP can be implemented using a variety of methods, such as using foreach loops and if statements, and using the in_array() and array_search() functions. Below is an example of performing a conditional query on an array in PHP using one of these methods.

Suppose you have an array called $students that contains the names and scores of multiple students. For example:

$students = array(

    array("name" => "小明", "score" => 80),
    array("name" => "小红", "score" => 90),
    array("name" => "小刚", "score" => 70),
    array("name" => "小丽", "score" => 85)

);

Now if you want to find the students who scored above 80, you can use a foreach loop and if statement to Implementation:

foreach($students as $student){
if($student['score']>=80){

echo $student['name']." ".$student['score']."分<br>";

}
}

The above code will iterate through each student in the $students array. If the student's score is greater than or equal to 80 points, the student's name and score will be printed. The output results are as follows:

Xiao Ming 80 points
Xiao Hong 90 points
Xiaoli 85 points

Another way to implement conditional query arrays is to use the in_array() function. For example, if you want to find if there is a student with a score of 90 in the $students array, you can use the following code:

if(in_array(90, array_column($students, 'score'))){
echo "There is a student with a score of 90";
}else{
echo "There is no student with a score of 90";
}

The above code uses in_array() The function searches for all scores in the $students array returned by the array_column() function. If there is a student with a score of 90, it prints out "There is a student with a score of 90", otherwise it prints "There is no student with a score of 90".

Finally, you can also use the array_search() function to conditionally query the array. For example, if you want to find Xiaohong's score, you can use the following code:

$key = array_search('Xiaohong', array_column($students, 'name'));
$score = $students$key;

The above code uses the array_search() function to find all names in the $students array, returns Xiaohong’s key, and then stores its score in the $score variable. Finally, you can use the echo statement to print Xiaohong's score.

In short, conditional query array in PHP is a very useful skill. Whether you need to find a specific element, or filter elements in an array by condition, you can easily do so using the methods above. Of course, this is just the tip of the iceberg of PHP array operations. In the process of learning PHP, you can also explore more interesting functions.

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