How to find all unique Names in a Matrix
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Hello,
I am trying to find all the unique names (Stocks Symbols) contained in the following 7500x7 Cell Matrix. Any suggestion on how to achieve the aimed result? The function ...
unique(Symbol)
does not seem to work.
Thank you
采纳的回答
>> A = {NaN,'cath','doug';NaN,'anna',NaN;NaN,'bob','eva';NaN,'anna','cath'}
A =
[NaN] 'cath' 'doug'
[NaN] 'anna' [ NaN]
[NaN] 'bob' 'eva'
[NaN] 'anna' 'cath'
>> unique(A(cellfun('isclass',A,'char')))
ans =
'anna'
'bob'
'cath'
'doug'
'eva'
This simply excludes any non-character values from the unique call, and is faster than calling an anonymous function as the first argument for cellfun:
>> temp(10000)
Elapsed time is 3.403746 seconds.
Elapsed time is 0.096025 seconds.
The timing file is attached here:
更多回答（3 个）
Image Analyst
2015-4-10
This seems to work:
% Create 2 by 3 cell array with 3 unique strings and NaNs.
ca = {nan, 'AAA', 'AAB'; nan, 'AC', 'AAA'}
ca2 = ca(:, 2:3); % Extract columns 2 & 3
% Find the 3 unique strings in columns 2 and 3
uniqueNames = unique(ca2)
What did you do differently?
Jon
2015-4-10
I think the problem is the NaNs. If you don't remove them, as Image Analyst does when defining ca2, the unique function seems to fail. If it's possible for NaN to be dispersed throughout the data, you'll need to exclude them from the unique command. The following might work for you.
UniSyms=unique(Symbol(cellfun(@(x) all(~isnan(x)),Symbol)));
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