(PHP 4, PHP 5, PHP 7)
implode — Join array elements with a string
$glue
, array $pieces
)$pieces
)
Join array elements with a glue string.
Note:
implode() can, for historical reasons, accept its parameters in either order. For consistency with explode(), however, it may be less confusing to use the documented order of arguments.
glueDefaults to an empty string.
piecesThe array of strings to implode.
Returns a string containing a string representation of all the array elements in the same order, with the glue string between each element.
Example #1 implode() example
<?php
$array = array('lastname', 'email', 'phone');
$comma_separated = implode(",", $array);
echo $comma_separated; // lastname,email,phone
// Empty string when using an empty array:
var_dump(implode('hello', array())); // string(0) ""
?>
Note: This function is binary-safe.
it should be noted that an array with one or no elements works fine. for example:
<?php
$a1 = array("1","2","3");
$a2 = array("a");
$a3 = array();
echo "a1 is: '".implode("','",$a1)."'<br>";
echo "a2 is: '".implode("','",$a2)."'<br>";
echo "a3 is: '".implode("','",$a3)."'<br>";
?>
will produce:
===========
a1 is: '1','2','3'
a2 is: 'a'
a3 is: ''
Can also be used for building tags or complex lists, like the following:
<?php
$elements = array('a', 'b', 'c');
echo "<ul><li>" . implode("</li><li>", $elements) . "</li></ul>";
?>
This is just an example, you can create a lot more just finding the right glue! ;)
Also quite handy in INSERT statements:
<?php
// array containing data
$array = array(
"name" => "John",
"surname" => "Doe",
"email" => "j.doe@intelligence.gov"
);
// build query...
$sql = "INSERT INTO table";
// implode keys of $array...
$sql .= " (`".implode("`, `", array_keys($array))."`)";
// implode values of $array...
$sql .= " VALUES ('".implode("', '", $array)."') ";
// execute query...
$result = mysql_query($sql) or die(mysql_error());
?>
It may be worth noting that if you accidentally call implode on a string rather than an array, you do NOT get your string back, you get NULL:
<?php
var_dump(implode(':', 'xxxxx'));
?>
returns
NULL
This threw me for a little while.
If you want to implode an array of booleans, you will get a strange result:
<?php
var_dump(implode('',array(true, true, false, false, true)));
?>
Output:
string(3) "111"
TRUE became "1", FALSE became nothing.
Even handier if you use the following:
<?php
$id_nums = array(1,6,12,18,24);
$id_nums = implode(", ", $id_nums);
$sqlquery = "Select name,email,phone from usertable where user_id IN ($id_nums)";
// $sqlquery becomes "Select name,email,phone from usertable where user_id IN (1,6,12,18,24)"
?>
Be sure to escape/sanitize/use prepared statements if you get the ids from users.
Safe way to pass as parameters in IN
<?php
$id_nums = array(1,6,12,18,24);
$p_types = '';
$qs = array();
foreach ($id_nums as $id) {
$qs[] = '?';
$p_types .= 'i'; // or whatever type
}
$nums_list = implode(',', $qs);
$sqlquery = "Select name,email,phone from usertable where user_id IN ($nums_list)";
$stmt = $dbh->stmt_init();
$stmt->prepare($sqlquery);
// later on, instead of bind:
$parms_array = array_merge(array($p_types), $id_nums);
call_user_func_array(array($stmt,'bind_param'), $parms_array );
// $sqlquery becomes "Select name,email,phone from usertable where user_id IN (?,?,?,?,?)"
?>
null values are imploded too. You can use array_filter() to sort out null values.
<?php
$ar = array("hello", null, "world");
print(implode(',', $ar)); // hello,,world
print(implode(',', array_filter($ar, function($v){ return $v !== null; }))); // hello,world
?>
in case you want to implode by keys:
<?php
const POSITION_KEY = 0;
const POSITION_VAL = 2;
const POSITION_DESC = 1;
$key = 'key';
$val = 'val';
$desc = 'desc';
$arr = array(
POSITION_KEY => $key,
POSITION_VAL => $val,
POSITION_DESC => $desc,
);
echo kimplode('=',$arr); // key=desc=val
echo '<br>';
echo krimplode('=',$arr); // val=desc=key
function kimplode($glue,$arr){
ksort($arr);
return implode($glue,$arr);
}
function krimplode($glue,$arr){
krsort($arr);
return implode($glue,$arr);
}
?>
