Arrays in PHP

  

Arrays in PHP: Introduction- What is an Array?

What is an array?

·        An array is a single variable that holds multiple data. In PHP, it enhances the scope and flexibility of variables.

·        When we create any variable, we can store just a single value, but an array provides the ability to store multiple values under a single variable name.

·        In PHP, we can store different types of data in a single element, like int, float, and character-like data in a list form.

·        PHP supports single-dimensional, two-dimensional, and multidimensional arrays.

·        There were three types of arrays

1.     Index array: In indexed arrays, array elements have a numerical index that starts from 0. Indexed array initialized as well as executed with numerical index.

2.     Associative array: Associative arrays allow us to create a named key for each element of an array. With this key, we can access or execute the array precisely.

3.     Multidimensional array: Multidimensional arrays allow us to create more than one array within an array. We can create it in an index or an associative format.

·        Array elements are stored and accessed by their index id, which starts from zero. Associative array stores and retrieves values by its key value(name). It makes it easier to handle and recognize which kind of data is stored.

·        We can create an array using the array function and square brackets [ ].

Example: Display array using HTML and PHP

<?php

$a=array("a1"=>array("rno"=>1,"name"=>"ram","city"=>"latur"),"a2"=>array("rno"=>2,"name"=>"ram","city"=>"latur"));

echo "<table border=1>";

echo "<hd><td>Rno</td><td>name</td><td>city</td></th>";

foreach($a as $x1=>$y1)

{ echo "<tr>";

            foreach($y1 as $x=>$y)

            {

 

echo"<td>$y</td>";

}

echo"</tr>";}

echo"</table>";

?>

OUTPUT

2.4 Types of Arrays: Indexed Vs. Associative arrays, Multidimensional arrays

Indexed arrays:

·       An Indexed array is a single variable that holds multiple data elements.

·       In indexed arrays, array elements have a numerical index that starts from 0.

·       An indexed array is initialized and executed with a numerical index. This numerical index is written with a pair of check braces [].

We can declare with a pair of square brackets [ ].

Syntax :

$array name = [];

$array name[0]= value1;

$array name[1]= value2;

$array name[2]= value3;

Example:

$a=[];

$a[0]= 1;

$a[1]= 2;

$a[2]= 3;

We can initialize an array in various ways, such as,

Syntax 1 with []:

$array name = [exp1,exp2…….exp n];

Example:

$a=[2,34,56,5];

Or

$a=[“Sunday”, ” Monday”, ” Tuesday”];

Syntax 2 with index number:

$arrayname[0]=value;

$arrayname[1]=value;

 ......

$arrayname[n]=value;

Example:

$a[0]=”Sunday”;

$a[1]=”Monday”;

 

$a[n]=”Tuesday”;

 Syntax 2 with array():

$ array name = array(exp1,exp2…….exp n);

Example:

$a=array(1,2,3);

Or

$a=array(“Sunday”, ” Monday”, ” Tuesday”);

How to execute indexed arrays in PHP?

Syntax:

Echo $arrayname [index value];

Example:

Echo $a[0];

Example:

<?php

$a=[];//array(); we can also use array function here.

$a[0]=1;

$a[1]=7;

$a[2]=13;

$a[3]=14;

$a[4]=15;

echo $a[0],"\n";

echo $a[1],"\n";

echo $a[2],"\n";

echo $a[3],"\n";

echo $a[4],"\n";

?>

OUTPUT

Execute an array with a for loop:

<?php

$a=[];

echo "INPUT\n";

for($a1=0;$a1<3;$a1++)

{

$a[$a1]=readline();

}

echo "\nOUTPUT\n";

for($a1=0;$a1<3;$a1++)

{

echo $a[$a1],"\n";

}

?>

Execute an array with a foreach:

<?php

$a=[“Sunday”, ” Monday”, ” Tuesday”];

foreach($a as $i)

{

echo $i,"\n";

}

?>

OUTPUT

Sunday

Monday

Tuesday

 Associative arrays:

·        Associative arrays allow us to create a named key for each element of an array.

·        With this key name, we can access or execute the array elements more precisely.

·        Associative key name followed by the “=>” operator, then value.

·        Rather than an index number, we can use a key name to retrieve array elements. We can also use a for loop and a Foreach loop to execute an array.

Declare or initialize values

Syntax with []:

$ array-name[“key-name”]=value;

WE can create an associative array individually, one by one, giving a specific name.

Example:

$a=[];

$ a[“n1”]=1;

$ a[“n2”]=2;

Access array:

$a=[];

$ a[“n1”]=readline();

$ a[“n2”]=readline();

Execute array:

Echo $a[“n1”];

Echo  $a[“n2”];

Syntax with array():

$array-name= array(“key1”=>value1, “key2”=>value2……..”key n”=>value n);

Example:

$a = array(“a”=>1,”b”=>2,”c”=>3);

Display an array:

Echo $a[“a”];

It will display the first element of the array.

Display array with foreach loop

<?php

$a=[“a1”=>“one”,”a2”=> ”Two”,”a3”=> ”Three”];

Foreach($a as $x=>$y)

{

Echo “$x=$y”

}

?>

OUTPUT

  A1=one  a2=Two    a3=Three

Example 1:

<?php

$a["rno"]=readline("Enter  roll number\t");

$a["name"]=readline("Enter  name\t");

$a["city"]=readline("Enter  city\t");

echo "roll no-\t".$a["rno"],"\n";

echo "Name-\t" ,$a["name"],"\n";

echo "City-\t",$a["city"],"\n";

 

?>

OUTPUT

Enter  roll number 1

Enter  name ram

Enter  city latur

roll no-        1

Name-   ram

City-   latur
Location: India

Comments

Post a Comment

Popular posts from this blog

The structure of HTML and some basic tags

Image
The structure of HTML ·         The structure of HTML   defined by a set of nested tags  like html ,head and a body tag  . What is tag? Tags are used to create elements, such as paragraphs, headings, links, images, and tables.   It is made up of the pair < ​​(less than sign)> (greater than sign).   Most HTML tags have an opening tag and a closing tag. The closing tag has the same text as the opening tag, but with an extra forward-slash (/) character. Structure of html  <html> <head><title> title </title></head> <body> </body> </html> Structure components  <!DOCTYPE html> : Declares the document as an HTML document. <html> : It is the root element of an HTML page. <head> : It contains meta information about the page. <title> : Display the title of the page. <body...
Read more

Frame tag and Example

Image
  Frame tag  Elements of frame tag The <frameset> tag provides us with the facility to divide our windows into multiple sections and each section has the same capability to execute individually. Attribute rows:  Rows divide our window into rows and the format of division is  <frameset rows=”50%,*”> or<frameset rows=”50%,50%”> Cols:  Cols divide our window into columns and the format of division                is  <frameset Cols =”50%, *”>   or <frameset Cols =”50%,50%”>   Border: Border provides border format at a pixel rate. Example:                                     <frameset border="1> <frame> tag: The frame tag provides a window frame with the src attribute. Attributes:  src: Src provides the URL of the to-be e...
Read more

Introduction and objective of HTML

Image
  Introduction to html What is HTML? HTML stand for Hypertext Markup Language. It is a computer language that defines the structure and content of web pages. It's language to build block of the web. In HTML, text can be structured into paragraphs, lists, images, and data tables. HTML can structure formatted content like paragraphs, lists, images, and data tables. HTML can create interactive elements like buttons that users can click to perform actions.  HTML can create links that connect web pages to one another.  We can customize  its appearance with CSS and JavaScript. Cascading Style Sheets (CSS) are used to describe a web page's appearance.  JavaScript provides us  functionality  to describe a web page's. JavaScript programming language provide functional to describe a web page's .  Characteristic of HTML  HTML uses markup to describe how to display text, images, and other content in a web browser.  Markup ...
Read more