What are Arrays in PHP ?
In PHP array is the collection of elements with common identifiers (identifiers are used to name variables , functions, constants, and classes),can have different Datatypes and continuous in memory .
Important points Related to Array in PHP
- To declare array ,array function is used $array[].
- In array subscript starts with \’Zero\'(0).
- In PHP Array can be declared without element.
- Array in PHP support interpolation.
- Array in PHP are using dynamic memory allocation ie they are resized automatically as element are assigned or added to array
Types Of Array:
- Indexed arrays – Arrays with numeric index
- Associative arrays – Arrays with named keys
- Multidimensional arrays – Arrays containing one or more arrays
How to define array in php?
$collect=array(\'red\',\'yellow\',\'123\',false); In above line $collect is array variable ,array is syntax of array function and red , yellow ,123,false are the element of array.
there are other ways to declare array in PHP
for example
$collection[]=\'city\';
$collection[]=\'phone\';
$collection[]=\'dob\'; in above example we are adding element in array $collection[] simply adding the value in array variable.
we also add element in array thru Index like
$collection[3]=\'sport\';
$collection[4]=\'school\';
these type of array called Indexed arrays these different method are used according to requirement .
To find out length of an array or number of element in array we can use count() function .
eg. count ($collection);
output will be 5 since we are added 5 element in array form 0-city to 4-school.
How to display or use the value of an array
- print_r($collection); function is use to print formatted output of an array.
- another method is to use for loop to use an array eg.
for($i=0;i<$n; $i++)
{
echo\"Element at i Index is $collection[$i]\";
}
Useful Function of array in PHP
- shuffle array
- sort array
- slice array
- merge array
Shuffle array : This function is use to shuffle or randomizes the order of the elements in an array.
Syntax: shuffle($array_name); Sort array : This function sort arrays in ascending order, To sort arrays in descending order we use rsort()
Syntax: sort($array_name); rsort($array_name)
Other sort function
- asort() – sort associative arrays in ascending order, according to the value
- ksort() – sort associative arrays in ascending order, according to the key
- arsort() – sort associative arrays in descending order, according to the value
- krsort() – sort associative arrays in descending order, according to the key
Slice array :if you wanted some element from an array then you can use slice function
$array = array_slice($array, 0, 2);
The second parameter is the start point ( 0 means to start from the beginning of the array).
The third parameter is the length of the resulting array
Merge array: To merge to array wen can use array_merge() function
$array = array_merge ($array1,$array2);
the above will result an array consisting element of both the array.
Array Function syantax |
Description of function |
|---|---|
| array() | Creates an array |
| array_change_key_case() | Changes all keys in an array to lowercase or uppercase |
| array_chunk() | Splits an array into chunks of arrays |
| array_column() | Returns the values from a single column in the input array |
| array_combine() | Creates an array by using the elements from one \”keys\” array and one \”values\” array |
| array_count_values() | Counts all the values of an array |
| array_diff() | Compare arrays, and returns the differences (compare values only) |
| array_diff_assoc() | Compare arrays, and returns the differences (compare keys and values) |
| array_diff_key() | Compare arrays, and returns the differences (compare keys only) |
| array_diff_uassoc() | Compare arrays, and returns the differences (compare keys and values, using a user-defined key comparison function) |
| array_diff_ukey() | Compare arrays, and returns the differences (compare keys only, using a user-defined key comparison function) |
| array_fill() | Fills an array with values |
| array_fill_keys() | Fills an array with values, specifying keys |
| array_filter() | Filters the values of an array using a callback function |
| >array_flip() | Flips/Exchanges all keys with their associated values in an array |
| array_intersect() | Compare arrays, and returns the matches (compare values only) |
| array_intersect_assoc() | Compare arrays and returns the matches (compare keys and values) |
| array_intersect_key() | Compare arrays, and returns the matches (compare keys only) |
| array_intersect_uassoc() | Compare arrays, and returns the matches (compare keys and values, using a user-defined key comparison function) |
| array_intersect_ukey() | Compare arrays, and returns the matches (compare keys only, using a user-defined key comparison function) |
| array_key_exists() | Checks if the specified key exists in the array |
| array_keys() | Returns all the keys of an array |
| array_map() | Sends each value of an array to a user-made function, which returns new values |
| array_merge() | Merges one or more arrays into one array |
| array_merge_recursive() | Merges one or more arrays into one array recursively |
| array_multisort() | Sorts multiple or multi-dimensional arrays |
| array_pad() | Inserts a specified number of items, with a specified value, to an array |
| array_pop() | Deletes the last element of an array |
| array_product() | Calculates the product of the values in an array |
| array_push() | Inserts one or more elements to the end of an array |
| array_rand() | Returns one or more random keys from an array |
| array_reduce() | Returns an array as a string, using a user-defined function |
| array_replace() | Replaces the values of the first array with the values from following arrays |
| array_replace_recursive() | Replaces the values of the first array with the values from following arrays recursively |
| array_reverse() | Returns an array in the reverse order |
| array_search() | Searches an array for a given value and returns the key |
| array_shift() | Removes the first element from an array, and returns the value of the removed element |
| array_slice() | Returns selected parts of an array |
| array_splice() | Removes and replaces specified elements of an array |
| >array_sum() | Returns the sum of the values in an array |
| array_udiff() | Compare arrays, and returns the differences (compare values only, using a user-defined key comparison function) |
| >array_udiff_assoc() | Compare arrays, and returns the differences (compare keys and values, using a built-in function to compare the keys and a user-defined function to compare the values) |
| array_udiff_uassoc() | Compare arrays, and returns the differences (compare keys and values, using two user-defined key comparison functions) |
| array_uintersect() | Compare arrays, and returns the matches (compare values only, using a user-defined key comparison function) |
| array_uintersect_assoc() | Compare arrays, and returns the matches (compare keys and values, using a built-in function to compare the keys and a user-defined function to compare the values) |
| array_uintersect_uassoc() | Compare arrays, and returns the matches (compare keys and values, using two user-defined key comparison functions) |
| array_unique() | Removes duplicate values from an array |
| array_unshift() | Adds one or more elements to the beginning of an array |
| array_values() | Returns all the values of an array |
| array_walk() | Applies a user function to every member of an array |
| array_walk_recursive() | Applies a user function recursively to every member of an array |
| arsort() | Sorts an associative array in descending order, according to the value |
| asort() | Sorts an associative array in ascending order, according to the value |
| compact() | Create array containing variables and their values |
| count() | Returns the number of elements in an array |
| current() | Returns the current element in an array |
| each() | Returns the current key and value pair from an array |
| end() | Sets the internal pointer of an array to its last element |
| extract() | Imports variables into the current symbol table from an array |
| in_array() | Checks if a specified value exists in an array |
| key() | Fetches a key from an array |
| krsort() | Sorts an associative array in descending order, according to the key |
| ksort() | Sorts an associative array in ascending order, according to the key |
| list() | Assigns variables as if they were an array |
| Sorts an array using a case insensitive \”natural order\” algorithm | |
| natsort() | Sorts an array using a \”natural order\” algorithm |
| next() | Advance the internal array pointer of an array |
| pos() | Alias of current() |
| prev() | Rewinds the internal array pointer |
| range() | Creates an array containing a range of elements |
| reset() | Sets the internal pointer of an array to its first element |
| rsort() | Sorts an indexed array in descending order |
| shuffle() | Shuffles an array |
| sizeof() | Alias of count() |
| sort() | Sorts an indexed array in ascending order |
| uasort() | Sorts an array by values using a user-defined comparison function |
| uksort() | Sorts an array by keys using a user-defined comparison function |
| usort() | Sorts an array using a user-defined comparison function |