Memory during a loop

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Aadil
Aadil 2012-9-6
Hi,
If I run Clear All during a loop, will it also clear the loop value?
Thanks,
  1 个评论
Aadil
Aadil 2012-9-6
ok it seems it does, is there any way round this, I'm reading large .mat data files, any way to only clear them and not the previous variables?

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采纳的回答

Jan
Jan 2012-9-6
As usual I mention, that clear all removes all loaded functions from the memory and reloading them from the disk and parsing them wastes a lot of time. When you want to clear variables, use
clear variables
However, Arthur's hint to use S=load() is very good. 1. it is easy to clear, 2. you cannot overwrite local variables by accident (as e.g. the loop counter...), 3. The debugging is much easier, because you can see on first sight, that "S.abcde" comes from the loaded file, and 4. Matlab is much faster with fixed names of variables compared to the ones created dynamically by EVAL or LOAD without catching the output.
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Aadil
Aadil 2012-9-7
hmm ok
so if I have:
for WhichVehicle = 1 : length(ProcessedFolderDirectories)
load(blahblah.mat)
run(blahblah)
clear variables
end
So it will only clear the variables then?

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更多回答（2 个）

Arthur
Arthur 2012-9-6
sure, you can just clear the variable:
clear varname
check:
doc clear
  3 个评论
显示 1更早的评论
Arthur
Arthur 2012-9-6
Do you need to load all the variables at once? You can also load a single variable at the time.
S = load(filename, variables)
This can be more memory efficient, but you may have to open the file multiple times...
Jan
Jan 2012-9-6
+1. Especially the suggested "S=load()" is a very good idea.

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Sean de Wolski
Sean de Wolski 2012-9-6
编辑：Sean de Wolski 2012-9-6
It depends on where you call it, compare:
  • 1
for ii = 1:10
ii
clear all
end
  • 2
for ii = 1:10
clear all
ii
end
But of course Arthur is right - you shouldn't need to use clear all at all.
  2 个评论
Aadil
Aadil 2012-9-6
is there any way to clear the last mat file loaded?
Sean de Wolski
Sean de Wolski 2012-9-6
Assign the *.MAT file you load to a variable then clear it when you're done. That way you aren't poofing variables into your workspace.
for ii = stuff
S = load('mymatfile.mat');
do_stuff_with(S)
clear S
end

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