Search column not working in the Google Spreadsheet script - google-apps-script

Question

I have a Google Spreadsheet with different columns and I've put as variable in my code var COLUMN_URL = 10 ;so now I would like to change in order to search the column URL which is in the first row of the sheet so I wrote this code :
var COLUMN_URL = function find_COLUMN_URL(){
var tss = SpreadsheetApp.openById(SPREADSHEET_ID);
var sheet = tss.getSheets()[0];
var data = sheet.getRange(1,1,1,1).getValues();
for(n=0;n<data.length;++n){
if(data[0][n].toString().match('URL')=='URL')
return n;
}
}
and I deleted the var COLUMN_URL = 10 but when I execute the code as I did with the previous declaration in the main fonction I doesn't work .Do you have an idea why is not working?Thank you.
Edit: I've changed in a different version like this :
function find_column_projet(){
var tss = SpreadsheetApp.openById(SPREADSHEET_ID);
var sheet = tss.getSheets()[0];
var lastColumn = sheet.getLastColumn() + 1;
var data = sheet.getRange(1,1,1,lastColumn).getValues();
for(n=0;n<data.length;n++){
if(data[0][n].toString().match('URL')=='URL')
COLUMN_URL = n + 1 ;
}
function show_URL(){
find_column_projet();
Logger.log('The URL ' + COLUMN_URL);
}
and in the log I have URL undefined and I don't get it where is the problem.I want to recuperate the first row and search for the URL and then return the number of the column.

Answer 1

I think you have forgotten to store the value returned by the find_column_projet() function, in the second version of your code:
function show_URL(){
var COLUMN_URL = find_column_projet();
Logger.log('The URL ' + COLUMN_URL);
}
The first iteration of your code is assigning COLUMN_URL to the function itself:
var COLUMN_URL = function find_COLUMN_URL(){
//...
}
when these operations should be separate:
function find_COLUMN_URL(){
}
var COLUMN_URL = find_COLUMN_URL();