What two array indexes mean when placed one after another?

Question

I'm just learning loops and can't get this part of the below script - what does values [i][0] mean here? (code found in this answer, described as a stopping condition). Is it the end and start of the array?

function getFirstEmptyRowByColumnArray() { 
  var ss = SpreadsheetApp.getActiveSpreadsheet(); 
  var values = ss.getRange('A:A').getValues(); 
  var i = 0; 

  while (values[i] && values[i][0] !== "") { 
    i++; 
  } 

  return i + 1;
}

The `getValues()` method returns a two dimensional array. The inner arrays represent each row. Each element an inner array represents a value in a spreadsheet cell. — Alan Wells, Apr 20 '16 at 01:08
@SandyGood Thank you. Am I right that applied to Google Sheets in the example code values[ i ] refers to a sheet's entire row, and values[ i ] [ 0 ] refers to a cell (i for row number, 0 for column)? — Viktor Zhurbin, Apr 20 '16 at 08:14

score 3 · Accepted Answer · edited May 23 '17 at 12:16

3

values is a more dimensional array. So the first index points to an array and the second index gives the element of that array. You can also imagine it as a matrix with rows and columns. The first index is the row and the second is the column.

If you want to know more about multi dimensional arrays in Javascript you can check out the answers to this question: How can I create a two dimensional array in JavaScript?

edited May 23 '17 at 12:16

Community

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answered Apr 20 '16 at 00:59

Martin Cup

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Thank you for the answer. Am I right that applied to Google Sheets in the example code values[ i ] refers to a sheet's entire row, and values[ i ] [ 0 ] refers to a cell (i for row number, 0 for column)? – Viktor Zhurbin Apr 20 '16 at 08:12
@VictorZhurbin Yes, the call ss.getRange( 'A:A' ).getValues() returns that data structure. – Martin Cup Apr 20 '16 at 08:15
That was fast :) Thank you once again! – Viktor Zhurbin Apr 20 '16 at 08:17

Ethan Brown · Answer 2 · 2016-04-20T01:18:04.700

2

Every array index operator (square brackets, aka computed member access aka bracket notation) accesses a single array element. So if you see them in series, you are dealing with an array of arrays (or it will result in an error). For example:

var arr = [
   [1, 2, 3], // inner array
   [4, 5, 6], // inner array
];
arr[0]         // [1, 2, 3]
arr[0][1]      // 2
arr[0][1][2]   // error: 2 is not an arry

edited Apr 20 '16 at 01:18

answered Apr 20 '16 at 01:00

Ethan Brown

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What two array indexes mean when placed one after another?

2 Answers2