How to compare two column in a spreadsheet - google-sheets

Question

I have 30 columns and 1000 rows, I would like to compare column1 with another column. IF the value dont match then I would like to colour it red. Below is a small dataset in my spreadsheet:
A B C D E F ...
1 name sName email
2
3
.
n
Because I have a large dataset and I want to storing my columns in a array, the first row is heading. This is what I have done, however when testing I get empty result, can someone correct me what I am doing wrong?
var index = [];
var sheet = SpreadsheetApp.getActiveSheet();
function col(){
var data = sheet.getDataRange().getValues();
for (var i = 1; i <= data.length; i++) {
te = index[i] = data[1];
Logger.log(columnIndex[i])
if (data[3] != data[7]){
// column_id.setFontColor('red'); <--- I can set the background like this
}
}
}
From the code you can see I am scanning whole spreadsheet data[1] get the heading and in if loop (data[3] != data[7]) compare two columns. I do have to work on my colour variable but that can be done once I get the data that I need.

Answer 1

Try to check this tutorial if it can help you with your problem. This tutorial use a Google AppsScript to compare the two columns. If differences are found, the script should point these out. If no differences are found at all, the script should put out the text "[id]". Just customize this code for your own function.
Here is the code used to achieve this kind of comparison
function stringComparison(s1, s2) {
// lets test both variables are the same object type if not throw an error
if (Object.prototype.toString.call(s1) !== Object.prototype.toString.call(s2)){
throw("Both values need to be an array of cells or individual cells")
}
// if we are looking at two arrays of cells make sure the sizes match and only one column wide
if( Object.prototype.toString.call(s1) === '[object Array]' ) {
if (s1.length != s2.length || s1[0].length > 1 || s2[0].length > 1){
throw("Arrays of cells need to be same size and 1 column wide");
}
// since we are working with an array intialise the return
var out = [];
for (r in s1){ // loop over the rows and find differences using diff sub function
out.push([diff(s1[r][0], s2[r][0])]);
}
return out; // return response
} else { // we are working with two cells so return diff
return diff(s1, s2)
}
}
function diff (s1, s2){
var out = "[ ";
var notid = false;
// loop to match each character
for (var n = 0; n < s1.length; n++){
if (s1.charAt(n) == s2.charAt(n)){
out += "–";
} else {
out += s2.charAt(n);
notid = true;
}
out += " ";
}
out += " ]"
return (notid) ? out : "[ id. ]"; // if notid(entical) return output or [id.]
}
For more information, just check the tutorial link above and this SO question on how to compare two Spreadsheets.