Chap 3php array part 2

Chapter 3
PHP
Array-part 2
1
Monica Deshmane(H.V.Desai college,Pune)

Topics
• Extracting multiple values
• Slicing an array
• Splitting of an array into chunks
• Retrieving keys & values
• Searching key or values
• splice
Monica Deshmane(H.V.Desai college,Pune) 2

Revision..

Introduction
•An array is a special variable, which can hold
more than one value at a time.
•It means it is continuous block of memory
locations.
•Arrays can be categorised using dimensions.
•1-D array
•2-D Array
•Multidimenstional array.
•In each category we have 2 types of arrays-
•Indexed Array
•Associative Array

Indexed Vs Associative Array
Indexed Arrays:
The keys of an indexed array are integers,
beginning at 0.
Indexed arrays are used when you identify
things by their position.
Associative arrays:
This array contains strings as keys and behave more
like two-column tables.
The first column is the key, which is used to access
the value.
PHP internally stores all arrays as associative arrays.

Extracting multiple values
OR multiple variable assignment
To copy all of an array's values into
variables, use the list( ) construct:
Which parameters required?
?
array
list($variable, ...) = $array;

Extracting multiple values/ multiple variable assignment
$book = array('C', 'Dennis Richie', 500);
list($n, $a, $p) = $book;
echo "Values : ".$n." ".$a." ".$p;
//Values : C Dennis Richie 500
$book = array('C', 'Dennis Richie', 500);
list($n, $a) = $book;
echo " Values : ".$n." ".$a." ";
//Values : C Dennis Richie

Extracting multiple values
$inventor= array('C', 'Dennis Richie');
list($n, $a, $p) = $inventor;
echo " Values : ".$n." ".$a." ".$p;
//Values : C Dennis Richie NULL
$values = range('a', 'e');
list($m,,$n,,$o) = $values; //,, for alternate elements
echo " Values : ".$m." ".$n." ".$o;
//Values : a c e

Slicing an array
To retrieve sub part of array
?
Array
Start index
No. of locations
$subset = array_slice(array, offset,[ length]);

Slicing an array
$sub = array('C', 'CPP', 'Java', 'PHP', 'DS');
$middle = array_slice($sub, 2, 3);
print_r($middle);
//Array ( [0] => Java [1] => PHP [2] => DS )
$book = array('C' => 'Richie' , 'CPP' => 'Bjarne', 'Java'
=> 'Sun', 'PHP'=>'Orelly');
$middle = array_slice($book, 1, 2);
print_r($middle);
//Array ( [CPP] => Bjarne [Java] => Sun )

Splitting of an array into chunks
?
$newarr=array_chunk($arr, chunk_size);
$nums = range(1, 7);
$rows = array_chunk($nums, 3);
print_r($rows);
// Array ( [0] => Array ( [0] => 1 [1] => 2 [2] => 3 )
[1] => Array ( [0] => 4 [1] => 5 [2] => 6 ) [2] =>
Array ( [0] => 7 ) )

Keys
?
$array_of_keys = array_keys(array);
$keys = array_keys($book);
//Array ( [0] => C [1] => CPP [2] => Java [3] => PHP )

Values
?
$array_of_values = array_values(array);
$values = array_values($book);
print_r($values);
//Array ( [0] => Richie [1] => Bjarne [2] => Sun [3]
=> Orelly )

To check perticular key
1) Checking Whether an Element Exists
$flag = array_key_exists(key, array)
$b = array_key_exists('Java', $book);
echo "Key exist : ".$b;
Returns true if exists false otherwise.
2)isset()
Same as array key exists but the difference is if key
contains value null it not returns true.

To check perticular value
1) Checking Whether an Element Exists
$flag = in_array(value, array)
$b =in_array (‘sun', $book);
echo “value exist : ".$b;
Returns true if exists false otherwise.

In_array in deep-Searching an array
in_array(search,array,type)
//type for strict type checking-true/false
$book = array("C", "CPP", "Java", "PHP", 10);
if (in_array("CPP",$book))
{
echo "Match found ";
}
else
{
echo "Match not found ";
}
//Match found

In_array in deep-Searching an array
if (in_array(“10",$book))
{
}
else
{
}
//Match found

Searching an array
if (in_array(“10",$book,true))
{
}
else
{
}
//Match not found

2)Array_search()
Same parameters as in_array()
Kay= array_search(value to serch,array);
$arr=array(“r"=>"red",“g"=>"green",“b"=>"blue");
echo array_search("red",$arr);
//returns key if value found
Output-
r

Revise…….
Extracting multiple values/ multiple variable assignment
List($a,$b)=$arr;
Slicing array-
$middle = array_slice($book, 1, 2);
Retrieving array of keys -
$array_of_keys = array_keys(array);
Retrieving array of values -
$array_of_keys = array_values(array);

Revise…….
Splitting of an array into chunks
$newarr=array_chunk($arr, chunk_size);
1) Checking Whether an Element key Exists
1)$flag = array_key_exists(key, array)
2)Isset()
1) Checking Whether an Element value Exists
In_array(value,array,type)
2) echo array_search("red",$arr);

Splice()
Removing and inserting elements in an array
?
$removed = array_splice(array, start,
[, length
[, replacement] ]);

Splice continue….
1. For removing array elements from start till length:
$sub = array('C', 'CPP', 'Java', 'PPL', 'DS', 'DBMS',
'SDK','ML');
$removed = array_splice($sub, 3, 2);
print_r($removed);
echo " ";
print_r($sub);
// Array ( [0] => PPL [1] => DS )
// Array ( [0] => C [1] => CPP [2] => Java [3] =>
DBMS [4] => SDK [5] => ML)

Splice continue….
2. For removing array elements to end of array:
$sub = array('C', 'CPP', 'Java', 'PHP', 'DS', 'DBMS',
‘NODE JS','ML');
$removed = array_splice($sub, 3);
print_r($removed);
echo " ";
print_r($sub);
// Array ( [0] => PHP [1] => DS [2] => DBMS [3] =>
NODE JS [4] => ML )
// Array ( [0] => C [1] => CPP [2] => Java )

Splice continue….
3. For inserting/ replacing array elements in an array:
$new_arr = array('Syspro', 'TCS', 'DDC');
'SDK','MFC');
$removed = array_splice($sub, 3, 2, $new_arr);
print_r($removed);
echo " ";
print_r($sub);
// Array ( [0] => PHP [1] => DS )
// Array ( [0] => C [1] => CPP [2] => Java [3] =>
Syspro [4] => TCS [5] => DDC [6] => MFC )

Splice continue….
4. For inserting array elements in an array without deleting:
$new_arr = array('Syspro', 'TCS', 'DAA');
'SDK','MFC');
$removed = array_splice($sub, 3, 0, $new_arr);
print_r($removed);
echo " ";
print_r($sub);
//Array ( )
//Array ( [0] => C [1] => CPP [2] => Java [3] => Syspro [4]
=> TCS [5] => DAA [6] => PHP [7] => DS [8] => DBMS [9]
=> SDK [10] => MFC )

Removing and inserting elements in an array
5. For removing array elements from associative
array:
$removed = array_splice($book, 1,2);
print_r($removed);
echo " ";
print_r($book);
//Array ( [CPP] => Bjarne [Java] => Sun )
//Array ( [C] => Richie [PHP] => Orelly )

Splice continue….
6. For inserting array elements into associative array:
$new_arr = array(‘new'=>‘xyz');
$removed = array_splice($book, 1,0, $new_arr);
//0 for insert without delete
print_r($removed);
echo " ";
print_r($book);
//Array()
//Array ( [C] => Richie [0] => xyz [CPP] => Bjarne
[Java] => Sun [PHP] => Orelly )

Chap 3php array part 2

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