What types of arrays are there in PHP7.0?

What are the types of arrays in PHP7.0?

Array is a very important data type in PHP7.0. It can store multiple values ​​and these values ​​can be accessed by index or key. In PHP 7.0, array types are very flexible and can therefore be used to solve many different programming problems. In this article, we will introduce the array types in PHP7.0 and how to use them.

1. Ordinary array

Ordinary array is one of the most common types in PHP7.0. It consists of an ordered list of key-value pairs, where the keys are of type integer or string and the values ​​can be of any data type. The following is an example of a normal array:

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

In the above code, we create a normal array consisting of "apple", "banana" and "orange" and store it in the $fruits variable middle. We can access the elements in the array through subscripts, as shown below:

echo $fruits[0]; //输出"apple"
echo $fruits[1]; //输出"banana"
echo $fruits[2]; //输出"orange"

2. Associative array

Associative array is an array composed of a list of key-value pairs, where the key is a character String type. In PHP, associative arrays are also called "dictionaries" or "hash tables". Here is an example of an associative array:

$grades = array("John" => 95, "Mary" => 87, "Bob" => 78);

In the above code, we have created an associative array where the student's name is the key and the grade is the value. We can access elements in the array through keys, as shown below:

echo $grades["John"]; //输出95
echo $grades["Mary"]; //输出87
echo $grades["Bob"]; //输出78

3. Multidimensional array

A multidimensional array is a special type of array that is composed of other arrays. In PHP, multidimensional arrays can be arbitrarily nested. The following is an example of a three-dimensional array:

$people = array(
    array("name" => "John", "age" => 23, "city" => "New York"),
    array("name" => "Mary", "age" => 34, "city" => "London"),
    array("name" => "Bob", "age" => 45, "city" => "Paris")
);

In the above code, we have created a three-dimensional array where each element contains a person's name, age, and city. We can access elements in the array through multiple subscripts, as shown below:

echo $people[0]["name"]; //输出John
echo $people[1]["age"]; //输出34
echo $people[2]["city"]; //输出Paris

4. Arrays and functions

In PHP7.0, there are many built-in functions for processing arrays function. Here are some commonly used functions:

1. count() - Returns the number of elements of an array
2. sort() - Sorts an array in ascending order
3. rsort() - Sort by Sort an array in descending order
4. shuffle() - Randomly shuffle the order of array elements
5. array_merge() - Merge two or more arrays into one array
6. array_key_exists() - Check if the given key exists in the array
7. in_array() - Check if the given value exists in the array

In addition to the built-in functions, we can also use foreach Loop through all elements in an array. The following is an example of a foreach loop:

foreach($grades as $name => $grade) {
    echo "$name 的成绩是 $grade 分。";
}

In the above code, the loop iterates through each element in the $grades array and stores the key and value in the $name and $grade variables. Then the name and grade of each student were printed.

Summary:

In PHP7.0, array types are very flexible and can be used to solve many different programming problems. We introduced ordinary arrays, associative arrays, and multidimensional arrays, as well as some commonly used array functions and loops. Whether you are a beginner or an experienced developer, you should master the use of arrays to take full advantage of PHP's powerful programming capabilities.

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