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How do I delete empty array among populated arrays?

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Eric
Eric 2013-9-16
Hi,
I have trial names that end with numbers e.g. _1 or _30. The number suffix does not increment by _1, _2, _3 etc because I am only reading a few one minute trials over a thirty minutes of data. If the condition is 30 minutes, then the data from these trials is being stored in a 1x30 structure even though 2-29 is empty because I am only reading in two trials; the data is written to a .mat file. Without changing the trial name, is there a function in MATLAB that only stores arrays that are populated.
I tried doing this:
tnum = str2num(fname(jtnum+1:j)); % trial number if there is one
tnum = tnum(~cellfun(@isempty,tnum));%keeps only populated cells
But I get an error saying: Input #2 expected to be a cell array, was double instead.
Therefore, I added a second line of code, tnum = mat2cell(tnum) to try and get around the error "error to be cell array..." but got an error saying "Matrix indices must be full double."
Any suggestion is much appreciated.
Eric
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Jan
Jan 2013-9-17
Thanks for the clarifications.
If fname is a string, str2num replies a number, which is stored in tnum. Then cellfun(@isempty, tnum) does not work, because tnum is not a cell, but a number.
The comment "keeps only populated cells" does not enlighten me concerning the purpose of this line. Because you check the emptiness of tnum in the IF command later, what about simply omitting the the complete "tnum = tnum(~cellfun(@isempty,tnum));" line?
Eric
Eric 2013-9-17
If I omit the line "tnum = tnum(~cellfun(@isempty,tnum)", then the code will run but the output is not what I want. Because in a case were I only have data for trials 1 and 30, trial type is stored as 1x30 structure. However 2-29 are empty i.e.
>> subj.power_(2)
ans =
ana: []
force: []
kin: []
mar: []
but
>> subj.power_(1)
ans =
ana: [1x1 struct]
force: [1x1 struct]
kin: [1x1 struct]
mar: [1x1 struct]
So, it is these empty structures 2-29 that I want to get rid of and end up with a structure of 1xnumber of trials with data.
Thanks, Eric

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回答（1 个）

Doug Hull
Doug Hull 2013-9-16
You are probably better off not having variables named like this in the first place.
Naming variables

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