PHP: implode - Manual

User Contributed Notes
implode

killroy at g m a i l dot c o m
16-May-2005 03:29


Here is another variation on Chris' function. I added a $skip_empty parameter. if it's set to TRUE the result string will not contain keys whose values are empty. Great for building query_strings. If the parameter is not given it behaves like the original function:



$a='1';

$b='';

$c='3';



INPUT: implode_assoc('=','&',array('a'=>$a,'b'=>$b,'c'=>$c),true);

OUTPUT: a=1&c=3



INPUT: implode_assoc('=','&',array('a'=>$a,'b'=>$b,'c'=>$c));

OUTPUT: a=1&b=&c=3



function implode_assoc($inner_glue,$outer_glue,$array,$skip_empty=false){

 $output=array();

 foreach($array as $key=>$item)

  if(!$skip_empty || $item){$output[]=$key.$inner_glue.$item;}

 return implode($outer_glue,$output);

}

tshort at cisco dot com
29-Apr-2005 09:20


Correction: I meant "passed by value", not "pass by reference". My mistake. Passing by reference would speed up any of these functions by avoiding the copy necessary for "by value.



Other solutions have problems with non-arrays as well. But it demonstrates that there are many ways to solve this problem. Adding checks for non-arrays and short arrays makes the solution less elegant, but safer. Other solutions should have included similar protections.



function english_list($array, $oxfordComma=0)

{

  if (!is_array($array)) return $array;

  if (count($array) <= 1) return join(", ", $array);

  $last = array_pop($array);

  return join(", ", $array) . ($oxfordComma ? "," : "") . " and " . $last;

}

Andy Morris
28-Apr-2005 07:27


It's always dangerous to give sweeping statements like "this will always work!". Your solution is much more elegant than mine, but perhaps it's a little too elegant for its own good! Try giving it an array with zero or one elements in it for example. You could say that folks shouldn't call it in that case, but you know folks... they like pushing the boundaries. :-)



Perhaps you meant to say that the array can be altered inside the function because it is passed "by value" rather than "by reference", or is that just a mixture of terminology from my C++ upbringing? Passing by reference would imply that you could alter the array inside the function and have that alter its value outside. Passing by value implies that any changes inside the function affect the local function copy only. In PHP, the latter is clearly the case, unless a variable is explicitly declared as global.



OK, that's my 2c.

tshort at cisco dot com
28-Apr-2005 03:54


/* 

  english_list()

This one works with anything, since the array is passed by reference, modifying it in the function via pop has no effect on the array outside the function. But it can't be done on one line, because the array_pop() must occur before the join().

*/



function english_list($array, $oxfordComma=0)

{

  $last = array_pop($array);

  return join(", ", $array) . ($oxfordComma ? "," : "") . " and " . $last;

}

Andy Morris
28-Apr-2005 12:19


Similar to a previous note, but this works for any length array, plus also works for arrays with key strings instead of integer keys! I know it's not strictly an implode() example, but it concerns what you might be considering using implode() to help you to do achieve...



<?php

// Return array as a comma separated list; final two elements separated

// by 'and' with an optional "Oxford" comma preceding the 'and'.

function english_list($array, $oxfordComma=0)

{

  $optionalComma = ( $oxfordComma ) ? "," : "";

  $str = "";

  $size = count( $array );

  $i = 0;

  foreach ( $array as $item ) {

    $str .= $item;

    $i++;

    if ( $i < $size - 1) $str .= ", ";

    elseif ( $i == $size - 1) $str .= $optionalComma." and ";

  }

  return $str;

}



// test the comma separated list function

echo english_list( array(), 1 )."<br>";

echo english_list( array("foo"), 1 )."<br>";

echo english_list( array("foo", "bar"), 0 )."<br>";

echo english_list( array("a" => "foo", "b" => "bar", "c" => "foobar"), 1 )."<br>";

echo english_list( array("foo", "bar", "foobar", "barfoo"), 0 )."<br>";

?>

memandeemail at gmail dot com
27-Apr-2005 08:06


/**

     * Like implode but with keys

     *

     * @param string[optional] $glue

     * @param array $pieces

     * @param string[optional] $hifen

     * @return string

     */

    function implode_with_key($glue = null, $pieces, $hifen = ',') {

        $return = null;

        foreach ($pieces as $tk => $tv) $return .= $glue.$tk.$hifen.$tv;

        return substr($return,1);

    }

davidpk212 at gmail dot com
14-Apr-2005 10:36


I made this function to create an english-readable list from an array.



<?php

function english_list($array, $oxfordcomma=1) {

  $count = count($array)-1;

  $last = $array[$count];

  unset($array[$count]);

  $str = join(", ", $array);

  if ($oxfordcomma) {

    $str .= ",";

  }

  $str .= " and $last";

  

  return $str;

}

?>



The optional parameter "oxfordcomma" indicates whether or not to use the Oxford comma (a comma before the "and").



Example:



<?php

print english_list(array("foo", "bar", "foobar", "barfoo"));

?>

Would produce:



foo, bar, foobar, and barfoo

01-Apr-2005 08:07


Here is another varriation on the below code. This is useful if you are trying to store data as a string to be returned to an array later.  It allows unlimited nested arrays to be both stored and extracted, but does not print out as pretty.



function implode_assoc_r2($inner_glue = "=", $outer_glue = "\n", $recusion_level = 0, $array = null)

{

   $output = array();



   foreach( $array as $key => $item )

       if ( is_array ($item) )

       {

           // This is value is an array, go and do it again!

           $level = $recusion_level + 1;

           $output[] = $key . $inner_glue . $recusion_level . $inner_glue . implode_assoc_r ($inner_glue, $outer_glue, $level, $item, $keepOuterKey);

       }

       else

           $output[] = $key . $inner_glue . $recusion_level . $inner_glue . $item;



   return implode($outer_glue . $recusion_level . $outer_glue, $output);

}



function explode_assoc_r2($inner_glue = "=", $outer_glue = "\n", $recusion_level = 0, $string = null)

{

       $output=array();

       $array=explode($outer_glue.$recusion_level.$outer_glue, $string);

       

       foreach ($array as $value)

       {

               $row=explode($inner_glue.$recusion_level.$inner_glue,$value);

               $output[$row[0]]=$row[1];

               $level = $recusion_level + 1;

               if(strpos($output[$row[0]],$inner_glue.$level.$inner_glue))

                       $output[$row[0]] = explode_with_keys_a($inner_glue,$outer_glue,$level,$output[$row[0]]);

       }    

       



       return $output;

}

php.net {at} nr78 {dot} net
30-Mar-2005 08:50


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());



?>

stefan
03-Mar-2005 11:47


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)"

?>

Geoff Eby
03-Mar-2005 10:29


A handy use of implode in a MySQL query



<?php 

$id_nums = array(1,6,12,18,24);



$id_nums = implode(" OR user_id=", $id_nums);

                 

$sqlquery = "Select name,email,phone from usertable where user_id=$id_nums";



// $sqlquery becomes "Select name,email,phone from usertable where user_id=1 OR user_id=6 OR user_id=12 OR user_id=18 OR user_id=24"

?>

phpWalter at torres dot ws
14-Sep-2004 01:45


Chris Ross (17-Aug-2004 11:18) gave us a great function 'implode_assoc'.



But it didn't handle multi-level array.



I know, a few others here added this "feature", but...



I've modified Chirs' function to be recursive.



Hope it helps someone.



/**

  * Method to recursivly implode a multi-dimensional array

  * Orginal: Chris Ross - 17-Aug-2004

  * Modified: Walter Torres - 09-14-2004

  **/

function implode_assoc_r($inner_glue = "=", $outer_glue = "\n", $array = null, $keepOuterKey = false)

{

    $output = array();



    foreach( $array as $key => $item )

        if ( is_array ($item) )

        {

            if ( $keepOuterKey )

                $output[] = $key;



            // This is value is an array, go and do it again!

            $output[] = implode_assoc_r ($inner_glue, $outer_glue, $item, $keepOuterKey);

        }

        else

            $output[] = $key . $inner_glue . $item;



    return implode($outer_glue, $output);

}

Chris Ross
17-Aug-2004 01:18


I took static's implode_with_keys, and converted into something I considered a little more programatically useful.  I would argue that this sort of functionality should maybe be added to PHP.



<?php

/* This isn't really DB function, but it's general...  This will */

/* act like the PHP implode() function, but for assoc. arrays... */

function implode_assoc($inner_glue, $outer_glue, $array) {

        $output = array();

        foreach( $array as $key => $item )

                $output[] = $key . $inner_glue . $item;



        return implode($outer_glue, $output);

}

?>



  It's the same as static's, really, but allows you to join the keys to the values with any arbitrary string, rather than hard-coding a '='.

john
26-Apr-2004 04:15


hi,

to prevent implode from putting the zero at the end, I use ksort().



example:



$val[1]="one";

$val[2]="two";

$val[0]="zero";

ksort($val);

echo implode(":",$val);

//will return "zero:one:two"

chris at hitcatcher dot com
28-Oct-2003 03:50


I found it neccesary to create a function that joins the contents of a single dimension from a 2-d array. Here's the code in case anyone else should need to do the same:





<?php


function join_2d($glue, $pieces, $dimension = 0){


    //joins the values of a single dimension in a 2-d array


    $rtn = array();


    foreach($piece as $key => $value){


        if(isset($value[$dimension])){


            $rtn[] = $value[$dimension];


        }


    }


    return join($glue, $rtn);


}


?>





The dimension argument can be a positive integer or a named index. Here is an example:





<?php


$testarray = array(array(1 => 'a', 'three' => 1),


                          array(1 => 'b', 'three' => 2),


                          array(1 => 'c', 'three' => 3),


                          array(1 => 'd', 'three' => 4),


                          array(1 => 'e', 'three' => 5));





print "<pre>"; print_r($testarray); print "</pre>";


print join_2d(", ", $testarray, 1) . "<br>";


print join_2d(", ", $testarray, 'three') . "<br>";


?>

dan at danposluns dot com
23-Aug-2003 01:04


*** MULTI-DIMENSIONAL ARRAY IMPLODE ***



First of all, it should be noted that the function in the previous note is not technically correct, as it glues the outside of the first piece. This is the problem faced by any function that wants to construct a set out of an array without the overhead of handling the boundary indexes. It also doesn't preserve the dimensional architecture.



Use this function when you want to call implode() on a multi-dimensional array and want the resulting string to preserve the architecture of the different dimensions. For example:



array ( 5, array (2, 4, 6), array (3, 6, 9, array (12)))



would be reduced to:



[ 5, [ 2, 4, 6 ], [ 3, 6, 9, [ 12 ] ] ]



Note that this does not preserve key values. If you need those, you are probably better off using serialize() and then replacing the tokens with your own symbols using the string functions.



Anyway, here is the code:



function mdImpode($x, $y)

{

    $a = (is_array($x)) ? '[ ' . array_reduce($x, 'mdImplode') . ' ]' : $x;

    $b = (is_array($y)) ? '[ ' . array_reduce($y, 'mdImplode') . ' ]' : $y;

    return $a . ', ' . $b;

}



Then to call it, use:



$result = '[ ' . array_reduce($pieces, 'mdImplode') . ' ]';



Note that you have to make manual changes if you want different glue or set symbols. There may be a more elegant solution, but this should be a good compromise between efficiency and simplicity (the manual says that array_reduce is iterative, so this should be pretty speedy).

gregrahkin
19-Jun-2003 12:10


This function will implode a multi-dimension array



function implode_r ($glue, $pieces){

 $out = "";

 foreach ($pieces as $piece)

  if (is_array ($piece)) $out .= implode_r ($glue, $piece); // recurse

  else                   $out .= $glue.$piece;

  

 return $out;

 }

james at globalmegacorp dot org
30-May-2003 09:13


As a followup to the implode_with_keys function posted by 'static', here's a corresponding explode_with_keys function I wrote:



function explode_with_keys($seperator, $string)

{

        $output=array();

        $array=explode($seperator, $string);

        foreach ($array as $value) {

                $row=explode("=",$value);

                $output[$row[0]]=$row[1];

        }

        return $output;

}

ulderico at maber dot com dot br
07-Oct-2002 12:39


'Implode' does not implodes recursively... It might quite useful implode recursively when you get a many Arrays values with keys that replaces themselves as:



http://server/file.php?arg[1]=123&arg[2]=312&arg[3]=543&arg[2]=abc



If you build this URL progressively it would a great a idea that the newest value indeed took the place of any older ones, thus:



http://server/file.php?arg[1]=123&arg[3]=543&arg[2]=abc



would be a better option;



If one uses $_SERVER['REQUEST_URI'], this sanitation would not happen, the URL string would be greater and greater everytime.



With implode_r (see below) it becomes easier to build a "sanitised" URL, the one that less likely will overflow the browser.



$URL = $_SERVER['PHP_SELF'];

$tmp = implode_r("&", $_REQUEST); /* So as to allow to get ANY VALUE (G/P) from the Browser... */

$URL .= "?".$tmp;



/* implode_r */

function implode_r($glue, $array, $array_name = NULL){

while(list($key,$value) = @each($array))

if(is_array($value))

                        $return[] = implode_r($glue, $value, (string) $key);

                else

                        if($array_name != NULL)

                                $return[] = $array_name."[".(string) $key."]=".$value;

                        else

                                $return[] = $key."=".$value;

                                

        return(implode($glue, $return));

}

sorry I couldn't format the code.

Cedric at isoca dot com
11-Jul-2002 12:39


Implode with an unset array will made a warning and fail, but is ok with an empty array.

So if you don't trust the content of the array, allways initialize it before :

  $param = array();

  [...]

  echo implode('&', $param);

static
14-May-2002 02:43


The one thing missing with this function is a way to add the keys. So I wrote this little function:



function implode_with_keys($glue, $array) {

        $output = array();

        foreach( $array as $key => $item )

                $output[] = $key . "=" . $item;



        return implode($glue, $output);

}

php at woodenpickle dot com
15-Mar-2002 12:55


Hey, I found a good use for implode() today. It came from a need to have a <select name=state multiple> box on the page that a person could select multiple states from and send those to a >SELECT * FROM customers WHERE state='$state'; query. But they need to be able to send just one state also. Well, I changes the html select box to say <select name=state[] multiple>. This turns $state into an array as you may know. I then, later on in the script, did this:



$count = count( $state );

if( $count > 1 ) {

     $states = implode( "'.'", $state );

     $result = $database->query( "SELECT * FROM currentOrders WHERE date>=$from AND date <=$to AND state IN ('$states')" );

}



//This takes care of multiple states, but if the user sent only one state, I catch it here:



foreach( $state as $value );

if( $value )

     $result = $database->query( "SELECT * FROM currentOrders WHERE date>=$from AND date<=$to AND state='$value'" );

else //This one will catch the ALL states option if they choose that.

     $result = $database->query( "SELECT * FROM currentOrders WHERE date>=$from AND date<=$to" );



Anyway, I thought I'd post this up here in case it might help someone. Or maybe someone could figure out a better way and enlighten us all.. Have fun.. Bob

implode

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