Slide môn học PHP session 5 working with arrays

Define an array An array is a variable that can store a set of values of the same data type  Each value in an array is termed as an element  Each element of an array can be referred

Working with Arrays

Session 13

 Function is block of code that has

performs a specified job

 Functions enhance the logical flow

 Define an array

 Create and use array

 Merge array

 Use single and multidimensional arrays

 Use array-related functions

Define an array

 An array is a variable that can store

a set of values of the same data type

 Each value in an array is termed as an element

 Each element of an array can be referred by an array name and an index

 An array index is used to access an element

 An index can be a number or a string

array() Function - I

values of array elements

comma to create an array

associative arrays

array() Function - II

Syntax for creating an array using the

array() function is:

$array_name =

array([key => ] value,

[key => ] value)

Array Identifier

element in an array

the array identifier is:

$array_name[key] = “element_value”;

Indexed Array

integer

array, if the index type is not

specified at the time of creating

an array

integer, such as 1, 20, or 123

Indexed Array - Example

Associative Array

 An array where the index type is string

 Index value must be specified within

double quotes

Associative Array - Example

Merging Arrays

two or more arrays

$merged_array_name =

array_merge($first_array, $second_array);

Merged Array - Example

Multidimensional Arrays

 Each element is an array

 Each element requires an array name and

multiple set of indices

 Syntax for creating a multidimensional

array is:

$array_name = array(

array(key => value), array(key => value))

Multidimensional Array - Example

Array-related Functions - I

 sort() - Arranges the element values into

an alphabetical order

 rsort() - Sorts the element values in the

descending alphabetical order

 arsort() - Sorts both associative and

Array-related Functions - II

 array_flip() - Converts the element

values to index values and index values

to element values

 array_intersect() - Identifies and

returns the common element value among

a group of arrays

 array_keys() - Displays all the key

indices of the specified array

 array_reverse() - Reverses the order of

the array elements

rsort() Function

descending alphabetical order

array_flip() Function

 Converts the element values to index

values and index values to element values

Summary - I

 A variable can store only one value at a time

 An array is a variable that can store a set

of values of the same data type

 Each value in an array is termed as an

element

 All the elements are referenced by a common

name

 An array index is used to access an element

 An index can be a number or a string

 If the index is a string, the array is an

Summary - II

 We can combine the element values of two or

more arrays This process is called as merging

arrays

 In a single-dimensional array, the element

includes only one level of key value pairs

 In the multidimensional array, each element is

an array Each element requires an array name

and multiple set of indices

 There are two types of arrays

Summary - III

index type is string

must be specified within double quotes

store another array within it

 sort()

 arsort()

 rsort()

 array_pop()