Trying to index an array and extract its values with a for loop.
22 views (last 30 days)
Show older comments
I have an table of probabilities and I want to index the table to determine if there is a probability in any of the three columns that is not 1 or 0, extract the row and put it into a new array. I'm fairly new to working with matlab so I'm sure there is a very simple way to do this but it is evading me. Any help would be great.
i = 1;
for scrs(i,:) ~= 1 || scrs(i,:) ~= 0
unclassifiable = scrs(i,:);
i = i+1;
disp('Unclassifiable nanoparticles detected.')
end
0 Comments
Accepted Answer
Cris LaPierre
on 11 Jan 2022
Edited: Cris LaPierre
on 11 Jan 2022
You might also find Ch 12: Programming helpful since it covers for loops.
For loops start with a declaration of a counter, which is automatically incremented each loop, and repeats a fixed number of times. Note that this approach assumes scrs only has 1 column of data. If that is not true, you will need to modify this approach.
for i = 1:size(scrs,2)
if scrs(i,:) ~= 1 || scrs(i,:) ~= 0
unclassifiable(i,:) = scrs(i,:);
disp('Unclassifiable nanoparticles detected.')
end
end
What you have written looks more like a while loop to me, which continue to loop as long as the conditional expression is true. However, this stops looping the first time scrs is 1 or 0. Note that this approach assumes scrs only has 1 column of data. If that is not true, you will need to modify this approach.
i = 1;
while scrs(i,:) ~= 1 || scrs(i,:) ~= 0
unclassifiable(i,:) = scrs(i,:);
i = i+1;
disp('Unclassifiable nanoparticles detected.')
end
Not sure which one you want so try them both to understand the difference.
More Answers (1)
Kevin Holly
on 11 Jan 2022
Below are two possible ways.
If data is in table,
t=table;
t.column1 = [1 2 3 4 0 3 4 2 3 4 0 3 1]';
t.column2 = [8 7 9 0 3 9 2 1 2 3 1 0 3]';
t.column3 = [9 0 9 7 2 1 8 3 9 2 3 0 1]';
t
t((t.column1==0),:)=[];
t((t.column2==0),:)=[];
t((t.column3==0),:)=[];
t((t.column1==1),:)=[];
t((t.column2==1),:)=[];
t((t.column3==1),:)=[];
t
If data is in matrix,
t = [1 2 3 4 0 3 4 2 3 4 0 3 1;8 7 9 0 3 9 2 1 2 3 1 0 3;9 0 9 7 2 1 8 3 9 2 3 0 1]'
index = (sum((t~=1).*(t~=0),2)==3)
t(index,:)
1 Comment
Ive J
on 11 Jan 2022
The second approach is not efficient; this is way faster:
index = all(t ~= 0 & t ~= 1, 2);
See Also
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!