Question

I have a php script to retrieve data from a MysQL databse following an ajax call. The data needs to be returned to the calling web page as a string representing a series of x,y values to be displayed on a scatter graph.

The required format which the php script needs to output to the calling page (which will pick it up from xmlhttp.responseText) is as follows:

[[1,1],[2,2],[3,3],[4,4],[5,5],[6,6],[7,7]]

What I am getting is:

[[0,”69.08″],[1,”53.53″],[2,”61.61″],[3,”72.04″],[4,”82.72″],[5,”103.76″]]

The PHP code I am using to build the return string is:

while ($row=mysql_fetch_array($res_Data,MYSQL_NUM)) { 

  $index[$i] = $i;
  $PointArray[0] = $i;
  $PointArray[1] = $row[1];
  $ReturnData[$i] = $PointArray;
  $i = $i + 1;
}

echo json_encode($ReturnData);

Interestingly, when I echo the data to a html table displayed on the calling page rather than setting it as a php array, no double quotes appear.

My questions is twofold:

(1) Is there a more elegant way of building the data string than what I have come up with which appears a bit clumsy?

(2) What’s the best way to remove the double quotes – should this be done server side or in the javascript function on the web page initiating the call?

Many thanks

Answer 1

If you don’t want quotes to appear – just don’t put a strings in array 😉

Replace your code to something like (I added (float) modifier before $row[1]):

while ($row=mysql_fetch_array($res_Data,MYSQL_NUM)) { 

  $index[$i] = $i;
  $PointArray[0] = $i;
  $PointArray[1] = (float)$row[1];
  $ReturnData[$i] = $PointArray;
  $i = $i + 1;
}

Or a little more compact:

while ($row=mysql_fetch_array($res_Data,MYSQL_NUM)) { 
  $index[$i] = $i; // what is it used for?
  $ReturnData[$i] = array($i, (float)$row[1]);
  $i++;
}