Google-sheets – get values from multiple URL’s in Google Spreadsheet. IMPORTDATA doesnt work

A couple of days of looking at your code and I think I may have a solution, but it's a little bit of a kludge.

You can create a function that returns a 2D array which will fill the cells below and to the right of the original cell. So I would try something like this: (sample sheet here)

= getSheetNames(2)

where your student sheets are after the second sheet, and use this custom function:

function getSheetNames(after) {

  var ss = SpreadsheetApp.getActiveSpreadsheet();

  if (arguments.length === 0) {
    after = 0;
  }
  var allSheets = ss.getSheets();
  var allSheetNames = [];
  var sheetCount = allSheets.length;

  for (var i = after; i < sheetCount; i++) {
    //as you're putting them all in one row, you don't use array wrappers
    allSheetNames.push(allSheets[i].getName());
    //because it's merged need to add extra cell
    allSheetNames.push('');
  }
  return allSheetNames;
}

Edit - as you are using one row and inserting into merged cells - I have made some changes

I wasn't able to reproduce your results. As a matter of fact, it worked perfectly.

What you tried to do is most probably the following:

In A1 you typed in =HYPERLINK(CONCATENATE("http://www.example.com/id/",A1);A1) and this yields an error of coarse.

Update

If you really want to get the result in A1, then you need to use a script.

Code

// global
var ss = SpreadsheetApp.getActiveSpreadsheet();

function onOpen() {
  var menu = [{name: "create URL", functionName: "createURL"}];
  ss.addMenu("URL", menu);
}

function onEdit(e) {
  var activeRange = e.source.getActiveRange();

  if(activeRange.getColumn() == 1) { 
    if(e.value != "") { 
      activeRange.setValue('=HYPERLINK("http://www.example.com/id/'+e.value+'","'+e.value+'")');
    }
  }
}

function createURL() {
  var aCell = ss.getActiveCell(), value = aCell.getValue();
  aCell.setValue('=HYPERLINK("http://www.example.com/id/'+value+'","'+value+'")');  
}

Explained:

The e.value will retrieve the cells value (only applicable a cell). The setValue() will add the concatenated string into the getActiveRange(). All is only executed when e.value contains something and the active range is in column A.

I've created an extra menu option as well, to be able access the script this way.

Example:

I've created an example file for you: onEdit URL builder
Add this script via Tools>Script editor, into the script editor. Press the "bug" button and you can use the script.