PHP - Arrays

An array is aa data structure that stores one or more similar type of values in a single value(PHP Arrays). For example if you want to store 100 numbers then instead of defining 100 variables its easy to define an array of 100 length.(PHP Arrays)

There are three different kind of arrays and each array value is accessed using an ID c which is called array index.

Numeric array - An array with a numeric index(PHP Arrays). Values are stored and accessed in linear fashion
Associative array - An array with strings as index. This stores element values in association with key values rather than in a strict linear index order.(PHP Arrays)
Multidimensional array - An array containing one or more arrays and values are accessed using multiple indices

NOTE: Built-in array functions is given in function reference PHP Array Functions

Numeric Array(PHP Arrays)

These arrays can store numbers, strings and any object but their index will be prepresented by numbers. By default array index starts from zero.

Example(PHP Arrays)

Following is the example showing how to create and access numeric arrays.

Here we have used array() function to create array. This function is explained in function reference.

<html>
<body>
<?php
/* First method to create array. */
$numbers = array( 1, 2, 3, 4, 5);
foreach( $numbers as $value )
{
  echo "Value is $value <br />";
}
/* Second method to create array. */
$numbers[0] = "one";
$numbers[1] = "two";
$numbers[2] = "three";
$numbers[3] = "four";
$numbers[4] = "five";

foreach( $numbers as $value )
{
  echo "Value is $value <br />";
}
?>
</body>
</html>

This will produce following result:

Value is 1
Value is 2
Value is 3
Value is 4
Value is 5
Value is one
Value is two
Value is three
Value is four
Value is five

Associative Arrays(PHP Arrays)

The associative arrays are very similar to numeric arrays in term of functionality but they are different in terms of their index. Associative array will have their index as string so that you can establish a strong association between key and values.

To store the salaries of employees in an array, a numerically indexed array would not be the best choice. Instead, we could use the employees names as the keys in our associative array, and the value would be their respective salary.

NOTE: Don't keep associative array inside double quote while printing otheriwse it would not return any value.

Example(PHP Arrays)

<html>
<body>
<?php
/* First method to associate create array. */
$salaries = array( 
     "mohammad" => 2000, 
     "qadir" => 1000, 
     "zara" => 500
    );

echo "Salary of mohammad is ". $salaries['mohammad'] . "<br />";
echo "Salary of qadir is ".  $salaries['qadir']. "<br />";
echo "Salary of zara is ".  $salaries['zara']. "<br />";

/* Second method to create array. */
$salaries['mohammad'] = "high";
$salaries['qadir'] = "medium";
$salaries['zara'] = "low";

echo "Salary of mohammad is ". $salaries['mohammad'] . "<br />";
echo "Salary of qadir is ".  $salaries['qadir']. "<br />";
echo "Salary of zara is ".  $salaries['zara']. "<br />";
?>
</body>
</html>

This will produce following result:

Salary of mohammad is 2000
Salary of qadir is 1000
Salary of zara is 500
Salary of mohammad is high
Salary of qadir is medium
Salary of zara is low

Multidimensional Arrays(PHP Arrays)

A multi-dimensional array each element in the main array can also be an array. And each element in the sub-array can be an array, and so on. Values in the multi-dimensional array are accessed using multiple index.

Example(PHP Arrays)

In this example we create a two dimensional array to store marks of three students in three subjects:

This example is an associative array, you can create numeric array in the same fashion.

<html>
<body>
<?php
   $marks = array( 
  "mohammad" => array
  (
  "physics" => 35,     
  "maths" => 30,     
  "chemistry" => 39     
  ),
  "qadir" => array
                (
                "physics" => 30,
                "maths" => 32,
                "chemistry" => 29
                ),
                "zara" => array
                (
                "physics" => 31,
                "maths" => 22,
                "chemistry" => 39
                )
      );
   /* Accessing multi-dimensional array values */
   echo "Marks for mohammad in physics : " ;
   echo $marks['mohammad']['physics'] . "<br />"; 
   echo "Marks for qadir in maths : ";
   echo $marks['qadir']['maths'] . "<br />"; 
   echo "Marks for zara in chemistry : " ;
   echo $marks['zara']['chemistry'] . "<br />"; 
?>
</body>
</html>

This will produce following result:

Marks for mohammad in physics : 35
Marks for qadir in maths : 32
Marks for zara in chemistry : 39

TUTORIALS POINT

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Saturday, 25 July 2015

PHP - Arrays

PHP - Arrays

Numeric Array(PHP Arrays)

Example(PHP Arrays)

Associative Arrays(PHP Arrays)

Example(PHP Arrays)

Multidimensional Arrays(PHP Arrays)

Example(PHP Arrays)

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