Some arrays operations September 17, 2008
Posted by Nsh15 in php, PHP Arrays, Variables and Data.Tags: Arrays in PHP, Exchanging keys and values, Finding array size, php, PHP Arrays, Removing duplicate items, Summing arrays
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Summing arrays:
To add all the elements in the array, use this statement:
$sum_result= array_sum($array_name);
If u try to add some elements which is not numbers, PHP will autiomatically convert them to number with the zero value!
Example:
<?php
$sum_array= array (1,2,3,4);
$sum_result = array_sum($sum_array);
echo “The sum of all elements in the \$sum_array = “,$sum_result;
?>
The output:
The sum of all elements in the $sum_array = 10
Removing duplicate items:
to remove duplicate items, use the following statement:
$array_without_duplicate_values= array_unique($array_name);
Example:
<?php
$aaray_with_duplicate= array (“A1″,”B1″,”C1″,”A1″);
$aaray_without_duplicate= array_unique($aaray_with_duplicate);
echo “The array with duplicate elements <br><pre>”;
print_r($aaray_with_duplicate);
echo “</pre>”;
echo “The array without duplicate elements<br><pre>”;
print_r($aaray_without_duplicate);
echo “</pre>”;
?>
The output:
The array with duplicate elements
Array
(
[0] => A1
[1] => B1
[2] => C1
[3] => A1
)
The array without duplicate elements
Array
(
[0] => A1
[1] => B1
[2] => C1
)
Exchanging keys and values:
To exchange values and keys in an arrays:
$array_exchanged= array_flip($array_name);
Example:
<?php
$array_to_flip = array (“A1″,”B1″,”C1″);
$array_exchanged= array_flip($array_to_flip);
echo “The array before fliping its value with its keys<br><pre>”;
print_r($array_to_flip);
echo “</pre>”;
echo “The array after fliping its value with its keys<br><pre>”;
print_r($array_exchanged);
echo “</pre>”;
?>
The output:
The array before fliping its value with its keys
Array
(
[0] => A1
[1] => B1
[2] => C1
)
The array after fliping its value with its keys
Array
(
[A1] => 0
[B1] => 1
[C1] => 2
)
Finding array size:
u can use count or sizeof statement to find the size of an array
$size_value= count($array_name);
$size_value= sizeof($array_name);
the number of elements will be stored in $size_value for each statement!
Example:
<?php
$array_to_find_size= array (“A1″,”B1″,”C1″,”A2″,”B2″,”C2″);
$size_count = count($array_to_find_size);
$size_sizeof= sizeof($array_to_find_size);
echo “Size of \$ array_to_find_size using count : “, $size_count,
“<br>Size of \$ array_to_find_size using sizeof : “, $size_sizeof;
?>
The output:
Size of $ array_to_find_size using count : 6
Size of $ array_to_find_size using sizeof : 6
comparing arrays September 17, 2008
Posted by Nsh15 in php, PHP Arrays, Variables and Data.Tags: Arrays in PHP, array_diff, array_intersect, comparing arrays, find diffrenet elements in an arry, find same elements in an array, php, PHP Arrays
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can identify the elements that r the same or the elements that r different.
To find different elements:
$difference_array= array_diff($array1, $array2, ….);
$difference_array contains the elements in array1 and not in array2 or the other arrays.
The order in which u list the arrays make a diffrenence.
To find arrays elements that differ in either value or key, use this statement:
$difference_array= array_diff_assoc($array1, $array2, ….);
To find same elements:
U can find the same elements in two arrays or more using:
$similar_array= array_intersect($array1, $array2, ….);
If u want both the value and the key to be the same, use:
$similar_array= array_intersect_assoc($array1, $array2, ….);
Example:
<?php
$array1_diff= array (“A1″,”B1″,”C1″,”A2″,”B2″,”C2″);
$array2_diff= array (“A1″,”B1″,”C1″);
$array3_diff= array (“A1″,”B1″,”C1″,”B2″,”C2″);
$diff= array_diff($array1_diff,$array2_diff,$array3_diff);
echo “The difference: <br> <pre>”;
print_r($diff);
echo “</pre>”;
$same= array_intersect($array1_diff,$array2_diff,$array3_diff);
echo “<br >The same elements: <br> <pre>”;
print_r($same);
echo “</pre>”;
?>
The output:
The difference:
Array
(
[3] => A2
)
The same elements:
Array
(
[0] => A1
[1] => B1
[2] => C1
)
splitting and merging arrays September 17, 2008
Posted by Nsh15 in php, PHP Arrays, Variables and Data.Tags: Arrays in PHP, array_merg, array_slice, merging arrays, php, PHP Arrays, splitting arrays
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PHP allows u to put arrays together or take ‘em a part.
Splitting arrays:
u can split an array by creating a new array that contains a subset of an existing array.
$sub_array_name = array_slice($array_name,n1,n2);
where n1: the sequence number of the element in where the new array should start & n2: the length of the new array.
Example:
<?php
$big_array= array(“A1″,”B1″,”C1″,”A2″,”B2″,”C2″);
$sub_array = array_slice ($big_array,0,4);
echo “we want the sub array to contain the first 4 elements from the big_array”;
echo “<pre>”;
print_r($sub_array);
echo “</pre>”;
?>
The output:
we want the sub array to contain the first 4 elements from the big_array
Array
(
[0] => A1
[1] => B1
[2] => C1
[3] => A2
)
Merging arrays:
Conversely; u can merg two or more array together using this statement:
$big_array = array_merg($array1,$array2, …. );
u can merge arrays with number keys or words; As well!
However, for the word key if the keys r the same in any of the elements the later element will overwrite the first element and u will lose ur first element !
But the case is not the same for the numbers key, bcz it will give each a unique number!!!
Example:
<?php
$array1["A"]= “AAA”;
$array1["B"]= “BBB”;
$array2["A"]= “aaa”;
$array_12= array_merge($array1,$array2);
echo “When there is two identical string keys the last one will
over write the first element<br>”;
echo “<pre>”;
print_r($array_12);
echo “</pre>”;
$array11= array (“A1″,”B1″,”C1″);
$array22= array (“A2″,”B2″,”C2″);
$array_1212= array_merge($array11,$array22);
echo “When there is two identical number keys, they will be given another key value<br>”;
echo “<pre>”;
print_r($array_1212);
echo “</pre>”;
?>
The output:
When there is two identical string keys the last one will over write the first element
Array
(
[A] => aaa
[B] => BBB
)
When there is two identical number keys, they will be given another key value
Array
(
[0] => A1
[1] => B1
[2] => C1
[3] => A2
[4] => B2
[5] => C2
)
Note:
If u need to merge arrays that have identical arrays, use
array_merge_recursive which creates multidimensional array when keys r identical (u won’t lose any elements this way)!
converting variables into arrays (and vice versa) September 17, 2008
Posted by Nsh15 in php, PHP Arrays, Variables and Data.Tags: Arrays in PHP, compact, Convert arrays into variables, Convert variables into arrays, extract, php, PHP Arrays
3 comments
sometimes u want the information in an array atored in variables that u can use in PHP statements or u need vaiables converted to array elements.
Convert array into variables:
Using the extract statement u can retrieve all the values from an array and insert each value into variables by using the key for the variable name. In other words, each array is copied into a variable named for the key.
extract($array_name);
Example:
<?php
$array_to_extract= array (“first_element” => “ABC”,
“second_element” => “DEF”, “third_element” => “GHI”);
extract($array_to_extract);
echo “After extracting the array it will gives us the following variables <br>”;
echo “First element is “, $first_element, “<br>”;
echo “Second element is “, $second_element, “<br>”;
echo “Third element is “, $third_element, “<br>”;
?>
The output:
After extracting the array it will gives us the following variables
First element is ABC
Second element is DEF
Third element is GHI
Convert variables into arrays:
Conversely, u can also convert a group of simple variables into an array using compact statemenet which copies the value from each specific variable name into an array element
$array_name= compact ($variable_name);
OR
$array_name= compact ($array_name);
in the first method u use the variable name directly, while in the second method u use an array that contains the names of the variables.
Example:
<?php
$array_index= array (“index1″,”index2″,”index3″);
$index1= “Hi!”;
$index2 = “Welcome 2 my blog”;
$index3 = “Noor”;
$array_to_compact1= compact(“index1″,”index2″,”index3″);
echo “Using the first method <br>”;
echo “<pre>”;
print_r($array_to_compact1);
echo “</pre>”;
$array_to_compact2= compact($array_index);
echo “Using the second method <br>”;
echo “<pre>”;
print_r($array_to_compact2);
echo “</pre>”;
?>
The output:
Using the first method
Array
(
[index1] => Hi!
[index2] => Welcome 2 my blog
[index3] => Noor
)
Using the second method
Array
(
[index1] => Hi!
[index2] => Welcome 2 my blog
[index3] => Noor
)
converting arrays into strings (and vice versa) September 17, 2008
Posted by Nsh15 in php, PHP Arrays, Variables and Data.Tags: Arrays in PHP, Convert array into a string, Convert string into array, explode, implode, php, PHP Arrays
3 comments
You can easily converte between arrays and strings, i.e.. u can ‘ve a sentence with each word of it in an array element!
Convert string into array:
u can create an array that contains the contents of a string by using this statement:
$array_name= explode(“s”,String);
- s: Is the character to use to divide the string
- String: string itself
Example:
<?php
$string_variable= “Hi:and:welcome:to:my:blog”;
$array_string = explode (“:”,$string_variable);
echo “Now lets print our new array <br>”;
echo “<pre>”;
print_r($array_string );
echo “</pre>”;
?>
The output:
Now lets print our new array
Array
(
[0] => Hi
[1] => and
[2] => welcome
[3] => to
[4] => my
[5] => blog
)
Convert array into a string:
Conversely, u can convert an array into string using:
$variable_name= implode (“s”,$array_name);
s: seprating the text from each array element and then store the string the $variable_name
Example:
<?php
$array_to_be_string= array (“hi”, “and”, “welcome”, “to”, “my”, “blog”);
$string_array= implode (” “,$array_to_be_string);
echo “The new string is <br>”, $string_array;
?>
The output:
The new string is
hi and welcome to my blog
Note: both emplode and implode doensn’t affect the input to the statmentm it just read it !
