10 important php functions with examples and explanation

PHP is a popular server-side scripting language widely used to develop dynamic web applications. It has evolved tremendously over the years with the addition of several advanced functions that have made PHP more efficient, secure, and user-friendly. In this article, we will discuss the top 10 important advance PHP functions that every PHP developer should know.

array_map():

The array_map() function applies a callback function to each element of an array and returns a new array containing the results. The syntax is as follows:

array_map(callback, arr1 [, arr2, …])

The parameters are:

callback: The function to apply to each element of the array.
arr1: The array to apply the function to.
arr2,…: Optional additional arrays to apply the function to.

The return type is an array. Here’s an example:

$numbers = [1, 2, 3, 4, 5]; function cube($n) {    return $n * $n * $n; } $cubed_numbers = array_map("cube", $numbers); print_r($cubed_numbers);

Output:

Array ( [0] => 1 [1] => 8 [2] => 27 [3] => 64 [4] => 125 )

array_reduce():

The array_reduce() function applies a callback function to each element of an array and returns a single value. The syntax is as follows:

array_reduce(array, callback [, initial])

The parameters are:

array: The array to apply the function to.
callback: The function to apply to each element of the array.
initial: Optional initial value to use as the accumulator.

The return type is the same as the initial value, or the type returned by the callback function. Here’s an example:

$numbers = [1, 2, 3, 4, 5]; function sum($a, $b) {     return $a + $b; } $total = array_reduce($numbers, "sum", 0); echo $total;

Output:

array_filter():

The array_filter() function filters the elements of an array using a callback function and returns a new array with only the elements that pass the test. The syntax is as follows:

array_filter(array, callback)

The parameters are:

array: The array to filter.
callback: The function to test each element of the array.

The return type is an array. Here’s an example:

$numbers = [1, 2, 3, 4, 5]; function is_even($n) { return $n % 2 == 0; } $even_numbers = array_filter($numbers, "is_even"); print_r($even_numbers);

Output:

Array ( [1] => 2 [3] => 4 )

array_walk():

The array_walk() function applies a callback function to each element of an array, passing the value by reference, and does not return a value. The syntax is as follows:

array_walk(array, callback [, userdata])

The parameters are:

array: The array to apply the function to.
callback: The function to apply to each element of the array.
userdata: Optional user-defined data to pass to the callback function.

There is no return type. Here’s an example:

$numbers = [1, 2, 3, 4, 5];function square(&$n) {    $n = $n * $n;}array_walk($numbers, "square");print_r($numbers);

Output:

Array([0] => 1[1] => 4[2] => 9[3] => 16[4] => 25)

in_array():

The in_array() function checks if a value exists in an array and returns true if found, false otherwise. The syntax is as follows:

`in_array(needle, haystack [, strict])`

The parameters are:

needle: The value to search for in the array. –
haystack: The array to search in. –
strict: Optional boolean value that specifies if the type of the needle should be checked as well.
The return type is a boolean.

Here’s an example:

$fruits = ["apple", "banana", "orange"];if (in_array("banana", $fruits)) {echo "Found banana!";} else {echo "Could not find banana.";}

Output:

Found banana!

array_keys():

The array_keys() function returns an array containing the keys of an array. The syntax is as follows:

`array_keys(array [, search_value [, strict]])`

The parameters are:

array: The array to get the keys from. –
search_value: Optional value to search for in the array. –
strict: Optional boolean value that specifies if the type of the search value should be checked as well.
The return type is an array.

Here’s an example:

$fruits = ["apple" => 1, "banana" => 2];$keys = array_keys($fruits);print_r($keys);

Output:

Array([0] => apple[1] => banana)

array_reverse():

The array_reverse() function returns a new array with the elements of an array in reverse order. The syntax is as follows:

array_reverse(array [, preserve_keys])

The parameters are:

array: The array to reverse.
preserve_keys: Optional boolean value that specifies if the keys should be preserved.

The return type is an array. Here’s an example:

$numbers = [1, 2, 3, 4, 5];$reversed_numbers = array_reverse($numbers);print_r($reversed_numbers);

Output:

Array(    [0] => 5    [1] => 4    [2] => 3    [3] => 2    [4] => 1)

implode():

The implode() function joins the elements of an array into a string using a specified separator. The syntax is as follows:

implode(separator, array)

The parameters are:

separator: The string to use as a separator.
array: The array to join.

The return type is a string. Here’s an example:

$fruits = ["apple", "banana", "orange"];$fruits_string = implode(", ", $fruits);echo $fruits_string;

Output:

apple, banana, orange

explode():

The explode() function splits a string into an array using a specified separator. The syntax is as follows:

explode(separator, string [, limit])

The parameters are:

separator: The string to use as a separator.
string: The string to split.
limit: Optional integer value that specifies the maximum number of elements to return.

The return type is an array. Here’s an example:

$fruits_string = "apple, banana, orange";$fruits = explode(", ", $fruits_string);print_r($fruits);

Output:

Array(    [0] => apple    [1] => banana    [2] => orange)

substr():

The substr() function returns a portion of a string starting at a specified position and with a specified length. The syntax is as follows:

substr(string, start [, length])

The parameters are:

string: The string to extract the substring from.
start: The starting position of the substring.
length: Optional integer value that specifies the length of the substring.

The return type is a string. Here’s an example:

$string = "Hello, world!";$substring = substr($string, 7, 5);echo $substring;

Output:

world

Conclusion:

These are just a few of the many advanced functions that PHP has to offer. Learning and mastering these functions will make you a more efficient and productive PHP developer. Whether you’re building web applications or working on other PHP projects, these functions will help you solve problems and achieve your goals. So start exploring these functions and take your PHP skills to the next level!

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