Append to file without adding newlines using PHP - php

Question

I want to take some integers from the apriori_main table and store them into a text file as comma separated values. For each iteration I use file_put_contents to write data on the next line. Using fwrite gives the same result.
The output I want in the text file is:
1,2,3,4
But the output I'm getting is:
1
,2
,3
,4
Here is the code snippet:
$y="";
$stmt='SELECT category FROM apriori_main where id='.$id.'';
$nRows = $conn->query('select count(category) from apriori_main where id='.$id.'')->fetchColumn();
echo $nRows;
$file = "/opt/lampp/htdocs/ghi.txt";
$f = fopen($file, 'a+'); // Open in write mode
$count=1;
foreach($conn->query($stmt) as $row)
{
if($count!=$nRows)
{
$user = $row['category']."\n";
$y=$user; $y=$y.",";
$str=$y; echo $y;
$count=$count+1;
}
else
{
$user = $row['category']."\n";
$y=$user; $str=$y; echo $y;
}
file_put_contents($file, $str, FILE_APPEND);
}
fclose($f);

Answer 1

This is all that is needed:
$stmt = 'SELECT category FROM apriori_main where id='.$id.'';
$file = "/opt/lampp/htdocs/ghi.txt";
foreach($conn->query($stmt) as $row)
{
$str[] = $row['category'];
}
file_put_contents($file, implode(',', $str));
// only use FILE_APPEND if needed for the next time to append
Loop through query result rows
Append category to an array
Implode array elements with a comma , and write to the file
So in short, you:
Don't need to query for the count
Don't need to open the file
Don't use \n that's a newline
Don't need to add the comma , in the loop
Don't write each loop iteration

Answer 2

I don't know what else you're doing with these values, but you seem to have a ton of unnecessary variable declaring.
I think you can effectively break all of this
$file = "/opt/lampp/htdocs/ghi.txt";
$f = fopen($file, 'a+'); // Open in write mode
$count=1;
foreach($conn->query($stmt) as $row)
{
if($count!=$nRows)
{
$user = $row['category']."\n";
$y=$user; $y=$y.",";
$str=$y; echo $y;
$count=$count+1;
}
else
{
$user = $row['category']."\n";
$y=$user; $str=$y; echo $y;
}
file_put_contents($file, $str, FILE_APPEND);
}
fclose($f);
Down to this (with only one file operation at the end)
$file = "/opt/lampp/htdocs/ghi.txt";
foreach($conn->query($stmt) as $row)
{
$y[] = $row['category'];
}
//output to screen
echo implode("<br>", $y);
//output to file
file_put_contents($file,implode(",", $y));