Am I creating dynamic variable names?

6 views (last 30 days)
hmhuang
hmhuang on 20 Nov 2021
Commented: hmhuang on 22 Nov 2021
After reading this thread, I am still not sure I have created "dynamic variable names", which should be avoided as suggested in that thread.
I have a code snippet as following:
data = [1, 2, 3];
centerX = data(1);
centerY = data(2);
centerZ = data(3);
% And use these variables afterwards
Should I avoid creating those (probably dynamic) variable names, i.e., centerX, centerY, centerZ to use those data and simply/directly use data(1), data(2), data(3) instead?
  3 Comments
hmhuang
hmhuang on 21 Nov 2021
  • matrix1, matrix2, matrix3, matrix4, ...
  • test_20kmh, test_50kmh, test_80kmh, ...
  • nameA, nameB, nameC, nameD, ...
hmhuang
hmhuang on 21 Nov 2021
Edited: hmhuang on 21 Nov 2021
@Stephen But now I understand those example given in that thread were dynamically created using eval, which is different from my hardcoded ones.

Sign in to comment.

Answers (1)

Sulaymon Eshkabilov
Sulaymon Eshkabilov on 20 Nov 2021
What you are doing here is not dynamic variable naming. You're assigning a new variable name from your already assigned data.
This example shows the dynamic variable naming and assigning values to the dynamically named variables (U and V):
for jj=1:5
eval(['V' num2str(jj) '= jj'])
eval(['U' num2str(jj) '= ' 'V' num2str(jj) '*jj'])
end
Which is NOT recommended to employ.
That is equivalent to:
V = 1:5;
U = V.*V;
This one is the recommended one.
  11 Comments
Image Analyst
Image Analyst on 22 Nov 2021
@hmhuang, no. He did not create the dynamically named variable. His variable names are hard coded. If the file was called foo.png, there is no variable created called foo. You could do that with eval() but as we've been discussing, that's not recommended so that's why he probably did not show it. However he's saying that some people think they want to do it because they don't realize the problems it can cause.

Sign in to comment.

Categories

Find more on Scope Variables and Generate Names in Help Center and File Exchange

Tags

Community Treasure Hunt

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

Start Hunting!