PHP explode function

PHP explode function

The explode function is used to split a string by a specified string into pieces i.e. it breaks a string into an array.

The explode function in PHP allows us to break a string into smaller text with each break occurring at the same symbol. This symbol is known as the delimiter. Using the explode command we will create an array from a string. The explode() function breaks a string into an array, but the implode function returns a string from the elements of an array.

for more details please visit http://php.net/manual/en/function.explode.php

array explode ( string $delimiter , string $string [, int $limit ] )

explode function request 3 parameters, but the last one is optional. Let see what are these parameters.

$delimiter - to break a string into smaller text with each break occurring at the same symbol, this would be the symbol
$string - String that you want to split
$limit - Limit is optional param but would may be tricky. You must concern following points when you are try to use limit.

• If limit is set and positive, the returned array will contain a maximum of limit elements with the last element containing the rest of string.
• If the limit parameter is negative, all components except the last -limit are returned.
• If the limit parameter is zero, then this is treated as 1.

Let see some example codes:

<?php
$str = 'one|two|three|four';

// positive limit
print_r(explode('|', $str, 2));

Above code will output the following:
Array
(
    [0] => one
    [1] => two|three|four
)

<?php
$str = 'one|two|three|four';

// negative limit (since PHP 5.1)
print_r(explode('|', $str, -1));

Above code will output the following:
Array
(
    [0] => one
    [1] => two
    [2] => three
)

<?php
$str = 'one|two|three|four';

// limit with 0 and 1 would be same
print_r(explode('|', $str, 0));

Above code will output the following:

Array
(
    [0] => one|two|three|four
)

PHP implode function

implode() Function

The implode function is used to join an elements of an array with a string.

The implode() function returns a string from elements of an array. It takes an array of strings and joins them together into one string using a delimiter (string to be used between the pieces) of your choice.

The implode function in PHP is easily remembered as "array to string", which simply means that it takes an array and returns a string. It rejoins any array elements and returns the resulting string, which may be put in a variable.

Let's take an example:

If you want to separate array values with a dashed (-), Following statement is just fine.

<?php

$array = array('XXX', 'TTT', '2123123');
$dash_separated = implode("-", $array);

var_dump($dash_separated);

It will output the result as follows :

string(15) "XXX-TTT-2123123"

Here are the tricky ways of implode will get naughty.

1) When try to implode with empty array.
eg:

<?php
//When using empty array it will return empty string even passed the glue 
var_dump(implode('hello', array()));

Above code will output empty string as :


string(0) ""


2) When try to implode with array with boolean.

eg:

<?php

//When imploding boolean values it will just return the values of true
var_dump(implode('',array(true, true, false, false, true)));

Above code will output only true(s) as :

string(3) "111"

Advanced usage of implode method

If you are dealing with sql functions the implode method is just perfect. try following codes:

<?php

//Quite handier with sql functions with arrays

$fields = array(
        'subject' => 'go green',
        'message' => 'i am going to take off!'
);

$sql = 'INSERT INTO table_name';
$sql .= " VALUES (`" . implode("`,`", array_keys($fields)) . "`)";
$sql .= " ('" . implode("','", $fields) . "')";

var_dump($sql);

$userIds = array(2, 32, 55, 200, 44);

$sql2 = "SELECT * FROM table_name";
$sql2 .= " WHERE 1 AND (id=" . implode(" OR id = ", $userIds) . ")";

var_dump($sql2);

Above codes will give the output as follows:


string(90) "INSERT INTO table_name VALUES (`subject`,`message`) ('go green','i am going to take off!')"
string(88) "SELECT * FROM table_name WHERE 1 AND (id=2 OR id = 32 OR id = 55 OR id = 200 OR id = 44)"

Happy coding ~