What is the array type of php array subscript?

In PHP, array is a very commonly used data structure, which can be used to save a set of data and can access and operate these data through subscripts. In PHP, array subscripts can be integers or strings, and the array type is determined by the subscript type.

For arrays that use integer subscripts, PHP calls them "indexed arrays", which is the most common array type. Typically, such an array is created by sequentially adding data to the array, with each new data element automatically assigned a unique integer subscript. For example, the following code creates an indexed array:

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

In this array, each fruit is assigned an integer subscript, which are 0, 1, and 2. You can use these subscripts to access data elements in the array, as shown below:

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

In addition to using integer subscripts, PHP also supports using strings as array subscripts, which are called "associative" array". Compared with indexed arrays, associative arrays make it easier to access data elements using custom subscripts. For example, the following code creates an associative array:

$person = array(
    "name" => "John",
    "age" => 30,
    "gender" => "male"
);

In this array, each data element has a custom string subscript, which are "name", "age", and "gender". You can use these subscripts to access data elements in the array, as shown below:

echo $person["name"];     // 输出 "John"
echo $person["age"];      // 输出 30
echo $person["gender"];   // 输出 "male"

It should be noted that when using a string as an array subscript, you need to add quotes, otherwise PHP will interpret the subscript Is a constant or variable name.

In addition to indexed arrays and associative arrays, PHP also supports the use of mixed-type arrays. This kind of array can use both integer subscripts and string subscripts, for example:

$mixed = array(
    "name" => "John",
    1 => "apple",
    "age" => 30,
    2 => "banana",
    "gender" => "male",
    3 => "orange"
);

In this array, the subscripts of the data elements are both integers and strings, and these subscripts can be used To access the data elements in the array, as shown below:

echo $mixed["name"];     // 输出 "John"
echo $mixed[1];          // 输出 "apple"
echo $mixed["age"];      // 输出 30
echo $mixed[2];          // 输出 "banana"
echo $mixed["gender"];   // 输出 "male"
echo $mixed[3];          // 输出 "orange"

In short, in PHP, arrays are very powerful and flexible data structures. You can freely use different types of arrays according to project needs for more Organize and manipulate data easily.

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