Loop is not reading from the first value in the array?
2 views (last 30 days)
Show older comments
Jasmine Karim
on 8 Aug 2018
Commented: Jasmine Karim
on 9 Aug 2018
I have a loop that is transferring data between two arrays, however, I'm not sure why it is not reading from the very first and last values. The first array (arrayA) looks like:
{'7'} {'ans'} {[1]}
{'7'} {'ans'} {[2]}
{'7'} {'ans'} {[3]}
second array (arrayB) looks like:
{'7' } {[101]} {[1]}
{'ans'} {[278]} {[1]}
{'7' } {[299]} {[2]}
{'ans'} {[300]} {[2]}
{'7' } {[432]} {[3]}
{'ans'} {[467]} {[3]}
With the following loop, IF the value in arrayA{a,3} matches that in arrayB{b,3}, i want the FIRST matching value to appear in arrayB{b,4} and the SECOND matching value to appear in arrayB{b,5}.
for a = 1:length(arrayA)
for b = 1:length(arrayB)
if arrayA{a,3}==arrayB{b,3}
arrayA{a,4} = arrayB{b,2};
arrayA{a,5} = arrayB{(b+1),2};
end
end
end
Right now, it looks like:
{'7'} {'ans'} {[1]} {[278]} {[299]}
{'7'} {'ans'} {[2]} {[300]} {[432]}
{'7'} {'ans'} {[3]} {[467]} {[467]}
What I would like however would be:
{'7'} {'ans'} {[1]} {[101]} {[278]}
{'7'} {'ans'} {[2]} {[299]} {[300]}
{'7'} {'ans'} {[3]} {[432]} {[467]}
2 Comments
Rik
on 8 Aug 2018
What is the goal of this code? What are you trying to achieve? Also, (b-1)+1 is just b, so is that a typo?
I think I would use ismember(arrayA,arrayB) to get a list of valid positions, but that is just a gut feeling without knowing a bit more about your goal and what sort of data to expect.
Accepted Answer
Fangjun Jiang
on 9 Aug 2018
It is because third column in B has duplicated values. For example, the result of the first loop (b=1) in the "for b = 1:length(arrayB)" loop is over-written by the second loop (b=2)
5 Comments
Fangjun Jiang
on 9 Aug 2018
for a = 1:size(arrayA,1)
Col=3;
for b = 1:size(arrayB,1)
if arrayA{a,3}==arrayB{b,3}
Col=Col+1;
arrayA{a,Col} = arrayB{b,2};
end
end
end
Note that size() is better than length() for your case.
More Answers (0)
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!