How to use a foreach loop, but do something different on the last iteration?

Question

This is probably a simple question, but how do you iterate through an array, doing something to each one, until the last one and do something different?

I have an array of names. I want to output the list of names separated by commas.

Joe, Bob, Foobar

I don't want a comma at the end of the last name in the array, nor if there is only one value in the array (or none!).

Update: I can't use implode() because I have an array of User model objects where I get the name from each object.

$users = array();
$users[] = new User();

foreach ($users as $user) {
    echo $user->name;
    echo ', ';
}

How can I achieve this and still use these objects?

Update: I was worrying too much about how many lines of code I was putting in my view script, so I decided to create a view helper instead. Here's what I ended up with:

$array = array();
foreach($users as $user) {
    $array[] = $user->name;
}
$names = implode(', ', $array);

Answer 1

$array = array('joe', 'bob', 'Foobar');
$comma_separated = join(",", $array);

output:

joe,bob,Foobar

Answer 2

Use implode:

$names = array('Joe', 'Bob', 'Foobar');
echo implode(', ', $names); # prints: Joe, Bob, Foobar

To clarify, if there is only one object in the array, the ', ' separator will not be used at all, and a string containing the single item would be returned.

EDIT: If you have an array of objects, and you wanted to do it in a way other than a for loop with tests, you could do this:

function get_name($u){ return $u->name; };
echo implode(', ', array_map('get_name', $users) ); # prints: Joe, Bob, Foobar

Answer 3

implode(', ', $array_of_names)

Answer 4

psuedocode....

integer sigh=container.getsize();
sigh--;
integer gosh=0;
foreach element in container
{
  if(gosh!=sigh)
    dosomething();
  else 
    doLastElementStuff();
  gosh++;
}

looking at all the other answers, it seems PHP has gotten a lot more syntactic S since I last wrote anything in it :D

Answer 5

Sometimes you might not want to use implode. The trick then is to use an auxiliary variable to monitor not the last, but the first time through the loop. vis:

$names = array('Joe', 'Bob', 'Foobar');
$first = true;
$result = '';
foreach ($names as $name)
{
   if (!$first)
      $result .= ', ';
   else
      $first = false;

   $result .= $name;
}

Answer 6

I personally found the fastest way (if you're into micro optimization) is:

  if(isset($names[1])) {
     foreach ($names as $name) {
       $result .= $name . ', ';
    }
    $result = substr($result, 0, -2);
  } else {
    $result = $names[0];
  }

isset($names[1]) is the fastest (albeit not so clear) way of checking the length of an array (or string). In this case, checking for at least two elements is performed.

Answer 7

I come accross this a lot building SQL statements etc.

$joiner = " ";
foreach ($things as $thing) {
    echo "  $joiner $thing \n";
    $joiner = ',';
}

FOr some reason its easier to work out the logic if you think of the ",", "AND" or "OR" as an option/attribute that goes before an item. The problem then becomes how to suppress the the "," on the first line.

Answer 8

I actually find it easier to create my comma delimited text a little differently. It's a bit more wordy, but it's less function calls.

<?php
$nameText = "";
for ($i = 0; $i < count($nameArray); $i++) {
if ($i == 0) {
$nameText = $nameArray[$i];
}
else {
$nameText .= "," . $nameArray[$i];
}
}

It adds the comma as a prefix to every name except where it's the first element if the array. I have grown fond of using for as opposed to foreach since I have easy access to the current index and therefore adjacent elements of an array. You could use foreach like so:

<?php
$nameText = "";
$nameCounter = 0;
for ($nameArray as $thisName) {
if ($nameCounter == 0) {
$nameText = $thisName;
$nameCounter++;
}
else {
$nameText .= "," . $thisName;
}
}