Conditionally formatting duplicate rows in google sheets - google-sheets

Question

I want to apply conditional formatting so that all the rows which match another row exactly are highlighted.
Let's say I have a spreadsheet like the following
| | a | b | c |
|---|---|---|---|
| 1 | A | B | C | // Matches row 3 and 6
| 2 | A | B | A | // Matches row 5
| 3 | A | B | C | // Matches row 1 and 6
| 4 | B | B | C | // Matches no other row
| 5 | A | B | A | // Matches Row 2
| 6 | A | B | C | // Matches row 1 and 3
| 7 | B | B | A | // Matches no other row
All the rows except for row 4 and 7 would be highlighted.
For to rows to be considered duplicates, the value of each/every cell in a given row must exactly match the value of the corresponding cell (cell in the same column) in a duplicate row.
My attempt so far can only return the values of rows with only the first 2 cells being duplicate and returns the concatenation of all the duplicate values in each row, which is very far away from what I want.
CC = arrayformula(A:A&" "&B:B&" "&C:C) returns a new row which is the concatenation of A, B, and C, which is coercing the cell values into strings so "1" and 1 which are not the same appear to be the same, and also doesn't work across the entire row (could do If I just kept adding Columns, but would look terrible).
=filter(unique(CC), arrayformula(countif(CC, unique(CC)) > 1)) CC is the returned value from the previous equation
This would output
A B C
A B A
Then I could add a conditional formatting rule with a custom formula that Highlights a row if it's concatenated contents "Match" one of the return values from the previous equation, but I don't know how to do that, and the previous equation is already pretty flawed.
Ideally I want a solution that involves no string concatenation or entering in all column names.

Answer 1

Let's go over what is needed to create this function.
1st you need to get the rows as a string to be able to compare them like you did. I didn't use space like you did because it takes place, but you can keep them.
=ARRAYFORMULA(A:A&B:B&C:C)
The issue with that is that since the formula will be on 3 column, we don't want it to become C:C&D:D&E:E so we have to fix the column.
=ARRAYFORMULA($A:$A&$B:$B&$C:$C)
Yay! Now we have a list of string that represent the "value" of each row. We can now count for each line how many times they are found. I used A2 cause I guess you have a header, but if you don't, simply replace it with A1.
=COUNTIF(ARRAYFORMULA($A:$A&$B:$B&$C:$C);A2&B2&C2)
We also have to fix the column here or the function will only work on the 1st one.
=COUNTIF(ARRAYFORMULA($A:$A&$B:$B&$C:$C);$A2&$B2&$C2)
And now all that's left is check if you want to see thoses who are unique or thoses who have matches
=COUNTIF(ARRAYFORMULA($A:$A&$B:$B&$C:$C);$A2&$B2&$C2)>1

Answer 2

This solution doesn't involved converting the values to strings, but it still requires adding a function for every column, so it's almost there.
=countifs(arrayformula($A:$A=$A1),TRUE,arrayformula($B:$B=$B1),TRUE,arrayformula($C:$C=$C1),TRUE)>1
It's just a conditional for each column conditional = arrayformula($A:$A=$A1) in a countifs, countifs(conditional, true).
I just need to make it so it can take the column values as an array which i'm guessing will require an arrayformula

Answer 3

There is a MUCH simpler way.
Load Conditional Formatting (under Format).
Select "custom formula is" (way at the bottom of the formula list)
Use the formula "=countif(A:A,A1)>1", where A is the column that contains the cells you want to be formatted for duplicates.