Using Arrays in PHP

Sabari · #61 08-21-2007, 03:33 AM

Regular Expressions

Exploding and imploding refers to changing between a string and an array. You can take a specific string and create an array out of the words or vice versa.

Using the explode command will create an array from a string.

Here is a sample string to start things off :
<?php
$pantry = "tomatoes,oranges,bananas,potatoes,bread,apple s";
?>

Now you have to figure out a common seperator element. In this case it is a comma seperating each word. In a normal sentence, it could be specifed as a space.

Time to explode this string into an array...
<?php
$pantry = "tomatoes,oranges,bananas,potatoes,bread,apple s";
$pantry_food = explode(",",$pantry);
?>

The array called $pantry_food now contains 6 elements. The array keys range from 0 to 5 and contains the values of tomatoes to apples.
Doing a quick array print out :
<?php
$count_total = count($pantry_food);
for ($counter=0; $counter<$count_total; $counter++){
$line = each ($pantry_food);
echo "$line[key] $line[value] <br />";
}
?>

Results as :

0 tomatoes
1 oranges
2 bananas
3 potatoes
4 bread
5 apples

Sabari · #62 08-21-2007, 03:34 AM

Implode()

So exploding breaks the data apart, imploding brings the data together. The implode command will take the data from an array and assemble it into a single string.

We will use the newly created array from above and implode it into a new string.
<?php
$new_pantry = implode(" ",$pantry_food);
?>

Imploding uses a separator element as well. In this case, it adds the separator between each of the array elements when it creates the new string. The above example is using a space this time.

The new string :
<?php
echo "$new_pantry";
?>

Has the value of :

tomatoes oranges bananas potatoes bread apples

raj · #63 08-21-2007, 03:51 AM

hi all,

can any one give solution for this array issue?...

i want to convert multi-dimensional array to single-dimensional array..

$firstArray =>
Array(

[0] = test
[1] = new
[2] =
Array(
[0] = hey
[1] =
Array(
[0] = innerarray
[1] = innertest
)
[3] = final

)

)

I want to change Above array like this....

Array(

[0] = test
[1] = new
[2] = hey
[3] = innerarray
[4] = innertest
[5] = final
}

can any one give the solution for multi-dimensional to single-dimensional array?

raj · #64 08-21-2007, 06:08 AM

hi all,

here i have given the internal array pointer functions & sample code :

functions:
next

- Returns the array value in the next place that's pointed to by the internal
array pointer, or FALSE if there are no more elements.

current or pos

- Every array has an internal pointer to its "current" element, which is
initialized to the first element inserted into the array.

prev
- Returns the array value in the previous place that's pointed to by the
internal array pointer, or FALSE if there are no more elements.

eg for :current,next,prev,end function

<?php
$transport = array('current', 'next', 'car', 'plane');
$mode = current($transport); // $mode = 'current';
$mode = next($transport); // $mode = 'next';
$mode = next($transport); // $mode = 'car';
$mode = next($transport); // $mode = 'plane';
$mode = prev($transport); // $mode = 'car';
$mode = end($transport); // $mode = 'plane';

reset

- reset() rewinds array's internal pointer to the first element and returns
the value of the first array element, or FALSE if the array is empty.

eg for :reset function
<?php

$array = array('step one', 'step two', 'step three', 'step four');

// by default, the pointer is on the first element
echo current($array); // "step one"

// skip two steps
next($array);
next($array);
echo current($array); // "step three"

// reset pointer, start again on step one
reset($array);
echo current($array); // "step one"

?>

Sabari · #65 08-21-2007, 08:46 AM

Array Count()

Counting the number of elements in an array uses a command called count.

First we will start with our original pantry array :
<?php
$pantry = array(
1 => "apples",
2 => "oranges",
3 => "bananas"
);
?>

Now to count how many elements are in this array...
<?php
$total_elements = count($pantry);
echo "There are $total_elements elements in the array.";
?>

This will produce the result :
There are 3 elements in the array.

Sabari · #66 08-21-2007, 08:53 AM

natcasesort()

natcasesort — Sort an array using a case insensitive "natural order" algorithm

Example: natcasesort()

<?php
$array1 = $array2 = array('IMG0.png', 'img12.png', 'img10.png', 'img2.png', 'img1.png', 'IMG3.png');

sort($array1);
echo "Standard sorting\n";
print_r($array1);

natcasesort($array2);
echo "\nNatural order sorting (case-insensitive)\n";
print_r($array2);
?>

The above example will output:

Standard sorting
Array
(
[0] => IMG0.png
[1] => IMG3.png
[2] => img1.png
[3] => img10.png
[4] => img12.png
[5] => img2.png
)

Natural order sorting (case-insensitive)
Array
(
[0] => IMG0.png
[4] => img1.png
[3] => img2.png
[5] => IMG3.png
[2] => img10.png
[1] => img12.png
)

Sabari · #67 08-21-2007, 08:55 AM

natsort()

natsort — Sort an array using a "natural order" algorithm

Example: natsort()
<?php
$array1 = $array2 = array("img12.png", "img10.png", "img2.png", "img1.png");

sort($array1);
echo "Standard sorting\n";
print_r($array1);

natsort($array2);
echo "\nNatural order sorting\n";
print_r($array2);
?>

The above example will output:

Standard sorting
Array
(
[0] => img1.png
[1] => img10.png
[2] => img12.png
[3] => img2.png
)

Natural order sorting
Array
(
[3] => img1.png
[2] => img2.png
[1] => img10.png
[0] => img12.png
)

Sabari · #68 08-21-2007, 08:57 AM

extract()

extract — Import variables into the current symbol table from an array

extract() returns the number of variables successfully imported into the symbol table.

Example: extract()

<?php

/* Suppose that $var_array is an array returned from
wddx_deserialize */

$size = "large";
$var_array = array("color" => "blue",
"size" => "medium",
"shape" => "sphere");
extract($var_array, EXTR_PREFIX_SAME, "wddx");

echo "$color, $size, $shape, $wddx_size\n";

?>

The above example will output:

blue, large, sphere, medium

Sabari · #69 08-21-2007, 09:03 AM

Multidimensional Arrays

In a multidimensional 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.

Example:

In this example we create a multidimensional array, with automatically assigned ID keys:

$families = array
(
"Griffin"=>array
(
"Peter",
"Lois",
"Megan"
),
"Quagmire"=>array
(
"Glenn"
),
"Brown"=>array
(
"Cleveland",
"Loretta",
"Junior"
)
);

The array above would look like this if written to the output:

Array
(
[Griffin] => Array
(
[0] => Peter
[1] => Lois
[2] => Megan
)
[Quagmire] => Array
(
[0] => Glenn
)
[Brown] => Array
(
[0] => Cleveland
[1] => Loretta
[2] => Junior
)
)

Sabari · #70 08-21-2007, 09:05 AM

print_r()

Print_r() outputs readable information about a variable. Though not an array-only function, this is actually one of the most useful functions out there when you are working with and debugging arrays. In the case of arrays, it allows you to see every key and the associated value.

<?php

$Array=array("http://www.yahoo.com", "http://www.internet.com", "http://www.google.com", "http://www.cnn.com", "http://www.php.net");

print_r($Array);
?>

This PHP snippet would output:

Array (
[0] => Yahoo!
[1] => internet.com - the Internet and IT Network from Jupitermedia Corp.
[2] => Google
[3] => CNN.com - Breaking News, U.S., World, Weather, Entertainment & Video News
[4] => PHP: Hypertext Preprocessor )

If you are trying to visualize what is inside of an array, or trying to track down an error within one, this function is an ideal tool.

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