Array array tutorial in PHP_PHP tutorial

Define array

An array is an ordered set of variables, where each variable is called an element.

1. Define array
You can use the array() language structure to create a new array. It accepts a number of comma-separated key => value parameter pairs.
array( [key =>] value , ... ) // key can be a number or a string // value can be any value
Example 1:

$phpjc = array(
0=>'word',
3=>'excel',
'outlook',
'access');
print_r($phpjc);
?>

The output results are as follows:

Array ( [0] => word [3] => excel [4] => outlook [5] => access )

Example 1 defines an array named phpjc, the value of the first element is: word, (Note: the array starts counting from 0), the second element is empty, and the third element is: excel , the fourth and fifth elements
are automatically generated later You can create an empty array by assigning an array() without parameters to a variable
Example 2:

$phpjc = array();
$phpjc[] = "one";
$phpjc[] = "two";
echo $phpjc[0]."
";
echo $phpjc[1];
?>

The output results are as follows:

one
two

2. Read array elements
Use a string index (or key) to access a value stored in an array
Example 3:

$phpjc = array("first"=>1,"second"=>2,"third"=>3);
echo $phpjc["second"];
$phpjc["third"]=5; //Change the value of the third element from "3" to "5"
echo $phpjc["third"];
?>

There are many array-related functions in PHP, which are explained one by one with examples: is_array(), n_array(), count(), array_push(), array_unshift(), array_merge(), array_pop(), array_shift(), sort()

1.is_array() function

Whether it is an array
-------------------------------------------------- ----------
2.in_array() function
If you have a large array and all you want to accomplish is to find the presence of a given value, you can use in_array() to return true or false. The following code will output "Not found in this array" - because you are looking for an "Alber" in $namesArray that does not exist.

Code
​$namesArray = array("Joe", "Jane", "Bob", "Mary", "Paul", "Eddie", "John");
​$lookingFor = "Albert";
​if (in_array($lookingFor, $namesArray)) {
echo "You've found it!";
} else {
echo "Not found in this array!";
}
?>

-------------------------------------------------- ------------

3.count() function
If you change the value of $lookingFor to "Mary", you will get the message "You've found it!" - because "Mary" is part of $namesArray.
If you want to count array elements, you can use the count() function:

$namesArray = array("Joe", "Jane", "Bob", "Mary", "Paul", "Eddie", "John");
$count = count($namesArray);
?>
The $count value will be 7.
-------------------------------------------------- ----------

4.array_push() function
You can add elements to any array, either at the beginning or end of an existing array. You can also use functions to create a new array containing two or more array elements. When merged each array will be in the desired order. If your array already has internal sorting, you will need to reorder the new merged array. Let's start by adding elements to the end of an existing array, using the function array_push():

Code
/* Create original array */
​$fruitArray = array("apple", "orange", "banana", "kiwi", "pear");
/* Add to original array */
​array_push($fruitArray, "grape", "pineapple", "tomato");
/* List each element by its key value*/
​while (list($key,$value) = each($fruitArray)) {
echo "$key : $value
";
}
?>

This will display:

0 : apple
1 : orange
2: banana
3: kiwi
4: pear
5: grape
6: pineapple
7: tomato

-------------------------------------------------- ------------
5.array_unshift() function
The code is very similar when you need to add an element to the beginning of an array. The only difference is the function name: array_unshift() instead of array_push().

Code
/* Create original array */
​$fruitArray = array("apple", "orange", "banana", "kiwi", "pear");
/* Add to original array */
​array_unshift($fruitArray, "grape", "pineapple", "tomato");
/* List each element by its key value*/
​while (list($key,$value) = each($fruitArray)) {
echo "$key : $value
";
}
?>

This will display:

0 : grape
1: pineapple
2: tomato
3: apple
4 : orange
5 : banana
6: kiwi
7: pear

-------------------------------------------------- ------------
6.array_merge() function
The function array_merge() merges two or more arrays.

Code
/* Create original array */
​$fruitArray = array("apple", "orange", "banana", "kiwi", "pear");
/* Create the second array */
​$vegArray = array("carrot", "green beans", "asparagus", "artichoke", "corn");
/* Combine into an array */
​$goodfoodArray = array_merge($fruitArray, $vegArray);
/* List each element by its key value*/
​while (list($key,$value) = each($goodfoodArray)) {
echo "$key : $value
";
}
?>

This will display:

0 : apple
1 : orange
2: banana
3: kiwi
4: pear
5: carrot
6: green beans
7: asparagus
8: artichoke
9: corn

Now that you have added elements and merged arrays, let's practice the delete element function. You can use the function array_pop() to remove an element from the end of an array. If the function array_shift() is used, an element is deleted from the beginning of an array. In fact, when you delete an element from an array, the element is still available to you - when you pop or shift an element from an existing array.

-------------------------------------------------- ------------

7.array_pop() function
Use the array_pop() function to remove a value from the end of an array:

Code
/* Create an array*/
​$fruitArray = array("apple", "orange", "banana", "kiwi", "pear");
/* Pop up a certain value at the end */
​$popped = array_pop($fruitArray);
/* List the contents of the new array and the popped-up values*/
​while (list($key,$value) = each($fruitArray)) {
echo "$key : $value
";
}
echo "
and finally, in $popped: $popped";
?>

This will display:

0 : apple
1 : orange
2: banana
3: kiwi
and finally, in $popped: pear

-------------------------------------------------- ----------
8.array_shift() function
Next, delete a value from the end of the array:

Code
/* Create an array*/
​$fruitArray = array("apple", "orange", "banana", "kiwi", "pear");
/* Remove a value from the head of the array */
​$shifted = array_shift($fruitArray);
/* List the contents of the new array and the removed values*/
​while (list($key,$value) = each($fruitArray)) {
echo "$key : $value
";
}
echo "
and finally, in $shifted: $shifted";
?>

This will display:

0 : orange
1 : banana
2: kiwi
3: pear and finally, in $shifted: apple

-------------------------------------------------- ------------
9.sort() function
There are many functions that can help you sort array elements. But I will demonstrate basic sorting to help you understand the process:

Code
/* Create original array */
​$fruitArray = array("apple", "orange", "banana", "kiwi", "pear");
/* Sort */
​sort($fruitArray);
/* Reset it to correctly display the array from beginning to end */
/* List each element by its key value*/
​while (list($key,$value) = each($fruitArray)) {
echo "$key : $value
";
}
?>

This will display:

0 : apple
1 : banana
2: kiwi
3 : orange
4: pear

http://www.bkjia.com/PHPjc/477440.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/477440.htmlTechArticleDefinition of array An array is an ordered set of variables, where each variable is called an element. 1. Define an array You can use the array() language structure to create a new array. It accepts a certain number...