# find 1s in the Matrix

2 views (last 30 days)
Matin jaberi on 29 Sep 2022
Answered: Matin jaberi on 30 Sep 2022
Hi All,
I have a matrix 31996x66 and i need to write a if/else and for loop to do following.
the for loop must got through column 48 to 65 and anywhere the number is 1 it goes 36 cells back ()to the same row and save the number and if zero doesnt do anything.
for example:
if in row 500 coulumn 50 number is 1 then (50-36=14) it should go to row 500 column 14 and take the number and save in new table.
At the end the new Matrix should be 31996x(number of values for 1 in each row.)
Matin jaberi on 29 Sep 2022
there might be many different ways to find the numbers I need but thats the simplest script i came up with to get what I need.

Walter Roberson on 29 Sep 2022
firstcol = 48;
lastcol = 65;
offsetcol = 14;
idx = firstcol:lastcol;
offsetidx = idx-offsetcol;
result = YourMatrix(:,offsetidx) .* (YourMatrix(:,idx) == 1);
at the end the new Matrix should be 31996x(number of values for 1 in each row.)
You cannot do that; there could be a different number of 1's in each row and numeric matrices cannot have a different number of columns in each row.
The above code outputs an array the size of the subset, with 0 for the entries where the condition was not met.
I notice, by the way, that 62-14 = 48, so columns 48, 49, 50, 51 both act as numeric sources (values to be fetched) and as control information about which values are to be fetched. Is that overlap desired?
##### 2 CommentsShowHide 1 older comment
Walter Roberson on 29 Sep 2022
firstcol = 48;
lastcol = 65;
offsetcol = 36;
idx = firstcol:lastcol;
offsetidx = idx-offsetcol;
result = YourMatrix(:,offsetidx) .* (YourMatrix(:,idx) == 1);

Matin jaberi on 30 Sep 2022
so the box highlighted yellow is col 48 where number ==1 and the green one is column 14 is the same row. this should apply only when number is ==1

### Categories

Find more on Loops and Conditional Statements in Help Center and File Exchange

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by