How do I combine all elements in an array using comma? - php

Question

I know this question has with out any doubt been asked a whole lot of times. I though can seem to find a solution. So forgive me if it's way to simple.
The question is how do access the end of a while loop.
E.g.
while($countByMonth = mysql_fetch_array($countByMonthSet)) {
$c = $countByMonth["COUNT(id)"];
echo $c . "," ;
}
How do I manage separate each value of the while loop by a comma but of course I don't want the comma at the end of the value.
In advance thank you very much for your help :)

Answer 1

You can:
1) Build a string, and remove the last character:
$c = '';
while ($countByMonth = mysql_fetch_array($countByMonthSet)) {
$c .= $countByMonth["COUNT(id)"] . ',';
}
$c = substr($c, 0, -1);
echo $c;
2) Build an array and use implode()
$c = array();
while ($countByMonth = mysql_fetch_array($countByMonthSet)) {
$c[] = $countByMonth["COUNT(id)"];
}
echo implode(',', $c);
Tip: You can use aliases in your query, like: SELECT COUNT(id) as count FROM .... Then you can access it as $countByMonth['count'], which looks cleaner IMO.

Answer 2

The simple1 solution:
$isFirst = true;
while($countByMonth = mysql_fetch_array($countByMonthSet)) {
$c = $countByMonth["COUNT(id)"];
if ($isFirst) {
$isFirst = false;
} else {
echo = ', ';
}
echo $c;
}
Alternatively, you could implode() the values. Or - perhaps easier to read/understand/maintain - concatenate it all into a string and remove the last "," (SO eats my whitespace; the string is comma-whitespace):
$list = '';
while($countByMonth = mysql_fetch_array($countByMonthSet)) {
$c = $countByMonth["COUNT(id)"];
$list .= $c . ', ';
}
echo substring($list, 0, -2); // Remove last ', '
(Several other answers propose the use of an accumulated array and then use implode(). From a performance perspective this method will be superior to string concatenation.)
1 See comments.

Answer 3

Alternatively you can do:
$arr = array();
while($countByMonth = mysql_fetch_array($countByMonthSet)) {
$arr[] = $countByMonth["COUNT(id)"];
}
echo implode(', ',$arr);

Answer 4

Or afterwards just trim it off with rtrim($c, ',')

Answer 5

While I think the implode solution is probably best, in situations where you can't use implode, think of the basic algorithm differently. Rather than "how can I add a comma behind every element but the last?" ask yourself "how can I add a comma before every element but the first?"
$str = '';
$count = count( $array );
if( $count ) {
$i = 0;
$str = $array[$i];
$i++;
while( i < $count ) {
$str .= ','.$array[$i];
$i++;
}
}
If you "shift" the first element, then you can use a foreach loop:
$str = '';
if( count( $array ) ) {
$str = array_shift( $array );
foreach( $array as $element ) {
$str .= ', '.$element;
}
}

Answer 6

Ty this:
int count;//
while(i)
{
count=i;
}