Warning: A non-numeric value encountered

Question

Recently updated to PHP 7.1 and start getting following error

Warning: A non-numeric value encountered in on line 29

Here is wha

Answer 1

$sn = 0;//increment the serial number, then add the sn to job
for($x = 0; $x<20; $x++)
{
$sn++;
$added_date = "10/10/10";
$job_title = "new job";
$salary = $sn*1000;
$cd = "27/10/2017";//the closing date
$ins = "some institution";//the institution for the vacancy 
$notes = "some notes here";//any notes about the jobs

$sn_div = "
".$sn."
";
$ad_div = "
".$added_date."
";
$job_div = "
".$job_title."
";
$salary_div = "
".$salary."
";
$cd_div = "
".$cd."
";//cd means closing date
$ins_div = "
".$ins."
";//ins means institution
$notes_div = "
".$notes."
";


/*erroneous line*/$job_no = "job"+$sn;//to create the job rows
$$job_no = "
".$sn_div.$ad_div.$job_div.$salary_div.$cd_div.$ins_div.$notes_div."
";

echo $$job_no;//and then echo each job

}

that's the code I had which looped and created new html div elements. The code worked fine and the elements were formed, but i got the same warning in the error_log.

After reading the useful other answers, I figured that I was summing up a string and a number in the erroneous line. So I changed the code at that line to

/*erroneous line*/$job_no = "job"&&$sn;//this is the new variable that will create the job rows

Now the code works as earlier but with no warnings this time. Hope this example would be useful to someone.