What is an PHP Array ?
Arrays are a Special type of variable that you can store multiple types of data in a single variable in general. But keep in mind that arrays store data not permanently. And another important thing is when we are talking about arrays, all data should have the same data type. We cannot store multiple data which have different data types.
As an example, if we create an array to store the name of customers, we cannot add their age as an integer into the array. All the data should be string ( text ) for this case.
We can divide the arrays mainly into 2 types by considering the behavior of arrays such as single and multi dimensional arrays. In Today we are going to learn about single dimensional arrays.
Single Dimensional Array | 1D Arrays
When we are talking about this type of array we can divide this also in two main types called index array and associative array. The main difference between index and associative array is, use integers as the keys for index array and use strings as the keys for associative array.
01. Index Array
The index arrays are one main type of the arrays as I mentioned before and this type of array use integers to present their key index. That’s why we called it as index array.
Create an array
We can use array() function to create an array in PHP. There are many ways to create an array in PHP.
Type 01
<?php
$users = array("Name 1", "Name 2", "Name 3");
?>
Type 02
<?php
$users = array();
$users[0] = "Name 1";
$users[1] = "Name 2";
$users[2] = "Name 3";
?>
Type 03 (if you need to add data to array loop through follow below way)
<?php
$users = array();
$sizeOfarray = 10;
for($i = 0; $i < $sizeOfarray; $i++) {
$users[$i] = $i;
}
?>
All the above types of array creations return the exact same output as a result. You can select any type from above types to your arrays.
Display data
Actually there are many ways to retrieve or display data of a array. In here I will show you 2 ways to retrieve data from an array.
If you need to display single value of an array , follow below path.
<?php
$users = array("Name 1", "Name 2", "Name 3");
echo “Hello ”. $users[0];
//Output : Hello Name 1
?>
If you need to display the whole array at once, follow the loop through path.
<?php
$users = array("Name 1", "Name 2", "Name 3");
$sizeOfarray = count($users);
for($i = 0; $i < $sizeOfarray; $i++) {
echo $users[$i];
echo "<br>";
}
?>
02. Associative Array
In Associative array we use string as the keys of the array. As an example if we need to create an array with user names of users, we should have to follow below way in this case.
Type 01
<?php
$users = array("user1"=>"Alex", "user2"=>"Roy", "user3"=>"Joe");
?>
Type 02
<?php
$users[“user1”] = "Alex";
$users[“user1”] = "Roy";
$users[“user1”] = "Joe";
?>
All the above types of array creations return the exact same output as a result. You can select any type from above types to your arrays.
Display data from Associative array.
Actually there are many ways to retrieve or display data of a array. In here I will show you 2 ways to retrieve data from an array.
If you need to display single value of an array , follow below path.
<?php
$users = array("user1"=>"Alex", "user2"=>"Roy", "user3"=>"Joe");
echo “Hello ”. $users[“user1”];
//Output : Hello Alex
?>
If you need to display the whole array at once, follow the loop through path.
<?php
$users = array("user1"=>"Alex", "user2"=>"Roy", "user3"=>"Joe");
foreach($users as $key => $value) {
echo "Key=" . $key . ", Value=" . $value;
echo "<br>";
}
?>
Push Array
push_array() is a function that you can use to insert one or more values into the already exist array.
<?php
$users=array("user1","user2");
array_push($users,"user3","user4");
print_r($users);
?>PHP Array Sort Functions
Sorting refers to ordering data in an increasing or decreasing fashion according to some linear relationship among the data items.
- sort() - sort arrays in ascending order
- rsort() - sort arrays in descending order
- 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
PHP Array Functions
| Function | Description |
|---|---|
| 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() | Deprecated from PHP 7.2. 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 |
| natcasesort() | 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 |
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