Nuanced Excel Question; calculating proportions - excel

Question

Fellow overflowers, all help is appreciated;
I have the following rows of values (always 7 values per row) of data in Excel (3 examples below), where data is coded as 1 or 2. I am interested in the 1's.
2, 2, 1, 2, 2, 1, 1.
1, 2, 2, 2, 2, 1, 2.
2, 2, 2, 1, 1, 1, 2.
I use the =MATCH(1,A1:G1,0) to tell me WHEN the first 1 appears, BUT now I want to calculate the proportion that 1's make up of the the remaining values in the row.
For example;
2, 2, 1, 2, 2, 1, 1. (1 first appears at point 3, but then 1's make up 2 out of 4 remaining points; 50%).
1, 2, 2, 2, 2, 1, 2. (1 first appears at point 1, but then 1's make up 1 out of the 6 remaining points; 16%).
2, 2, 2, 1, 1, 1, 2. (1 first appears at point 4, but then 1's make up 2 out of the 3 remaining points; 66%).
Please help me calculate this proportion!

Answer 1

You could use this one
=(LEN(SUBSTITUTE(SUBSTITUTE(MID(A1,SEARCH(1,A1)+3,1000)," ",""),",",""))
-LEN(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(MID(A1,SEARCH(1,A1)+3,1000)," ",""),",",""),1,""))
)/LEN(SUBSTITUTE(SUBSTITUTE(MID(A1,SEARCH(1,A1)+3,1000)," ",""),",",""))
The
SUBSTITUTE(SUBSTITUTE(MID(A1,SEARCH(1,A1)+3,1000)," ",""),",","")
-part gets the string after the first 1. The single 1 in the middle part is the one, you want to calculate the percentage for. So if you want to adapt the formula to other chars, you have to change the single 1 in th emiddle part and the three 1s in the three searches.
EDIT thank you for the hint #foxfire
A solution for values in columns would be
=COUNTIF(INDEX(A1:G1,1,MATCH(1,A1:G1,0)+1):G1,1)/(COUNT(A1:G1)-MATCH(1,A1:G1,0))

Answer 2

You can do it with SUMPRODUCT:
My formula in column H is a MATCH like yours:
=MATCH(1;A3:G3;0)
My formula for calculatin % of 1's over reamining numbers after first 1 found, is:
=SUMPRODUCT((A3:G3=1)*(COLUMN(A3:G3)>H3))/(7-H3)
This is how it works:
(A3:G3=1) will return an array of 1 and 0 if cell value is 1 or not. So for row 3 it would be {0;0;1;0;0;1;1}.
COLUMN(A3:G3)>H3 will return an array of 1 and 0 if column number of cell is higher than column number of first 1 found, (that matchs with its position inside array). So for row 3 it would be {0;0;0;1;1;1;1}
We multiply both arrays. So for row 3 it would be {0;0;1;0;0;1;1} * {0;0;0;1;1;1;1} = {0;0;0;0;0;1;1}
With SUMPRODUCT we sum up the array of 1 and 0 from previous step. So for row 3 we would obtain 2. That means there are 2 cells with value 1 after first 1 found.
(7-H3) will just return how many cells are after first 1 found, so fo row 3, it means there are 4 cells after first 1 found.
We divide value from step 4 by value from previous step, and that's the % you want. So for row 3, it would be 2/4=0,50. That means 50%
update: I used 2 columns just in case you need to show where is the first 1. But in case you want a single column with the %, formula would be:
=SUMPRODUCT((A3:G3=1)*(COLUMN(A3:G3)>MATCH(1;A3:G3;0)))/(7-MATCH(1;A3:G3;0))