Changing Double to String Automatically in a Dataset Array
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Hi there,
I have a dataset array called 'data' of 2738 observations with 9 columns(2738*9) in size.
The 3rd column header is 'Surf' and contains 1's, 10's, 100's, 1000's, 10000's and 100000's.
I intend to write a for loop that goes through the data.surf column and wherever it sees a 1 it replaces it with 'F' and similarly replaces 10's with 'R' and so forth.
It seems as though I can replace the whole column with a 'F' by just typing in data.surf = 'F' but I am not quite sure how to write a mini script that automates this process. Any help or guidance will be appreciated.
Thanks in advance. Nj
1 Commento
Azzi Abdelmalek
il 26 Dic 2012
Modificato: Azzi Abdelmalek
il 26 Dic 2012
Is data a struct variable? (data.surf = 'F')
Risposta accettata
Teja Muppirala
il 27 Dic 2012
Here are two ways to do it:
%% Method 1, using "containers.Map"
ds = dataset([10;100;10;1000;100000;1;1;10000],'VarNames','Surf');
C = containers.Map([1 10 100 1000 10000 100000],{'F' 'R' 'A' 'B' 'C' 'D'});
ds.Surf = C.values(num2cell(ds.Surf))
%% Method 2, using ISMEMBER
ds = dataset([10;100;10;1000;100000;1;1;10000],'VarNames','Surf');
C = {[1 10 100 1000 10000 100000]; {'F'; 'R'; 'A'; 'B'; 'C'; 'D'}};
[~,loc] = ismember(ds.Surf,C{1});
ds.Surf = C{2}(loc)
6 Commenti
Teja Muppirala
il 27 Dic 2012
If you need to do be able to reverse the operation also, then I think the ISMEMBER way might be simpler. You could still do it either way though:
%% Using containers.Map
ds = dataset([10;100;10;1000;100000;1;1;10000],'VarNames','Surf');
C = containers.Map([1 10 100 1000 10000 100000],{'F' 'R' 'A' 'B' 'C' 'D'});
ds.Surf = C.values(num2cell(ds.Surf))
Cinv = containers.Map({'F' 'R' 'A' 'B' 'C' 'D'},[1 10 100 1000 10000 100000]);
ds.Surf = cell2mat(Cinv.values(ds.Surf))
%% Using ISMEMBER with an appropriate cell array
ds = dataset([10;100;10;1000;100000;1;1;10000],'VarNames','Surf');
C = {[1; 10; 100; 1000; 10000; 100000]; {'F'; 'R'; 'A'; 'B'; 'C'; 'D'}};
[~,loc] = ismember(ds.Surf,C{1});
ds.Surf = C{2}(loc)
[~,loc] = ismember(ds.Surf,C{2});
ds.Surf = C{1}(loc)
Più risposte (3)
Sean de Wolski
il 26 Dic 2012
So something like this?
ds = dataset(rand(10,1)>0.5,'VarNames','Surf');
idx = ds.Surf;
ds.Surf = repmat('F',numel(idx),1);
ds.Surf(idx) = 'T';
ds.Surf
4 Commenti
Walter Roberson
il 27 Dic 2012
If you are looking at data.surfs(K) then the new thing to write would be something like data.surfcodes(K)
Walter Roberson
il 26 Dic 2012
letteridx = 1 + round(log10(data.surf);
letters = 'FRXUH';
data.surf = letters(letteridx);
2 Commenti
Walter Roberson
il 27 Dic 2012
Could you show max(data.surf) before this code?
I notice that I should have allowed one more letter,
letters = 'fRSXUH';
Change the XUH to the appropriate codes for 1000, 10000, and 100000
Peter Perkins
il 9 Gen 2013
Nj, you might also consider using an ordinal variable here:
>> ds = dataset([10;100;10;1000;100000;1;1;10000],'VarNames','Surf')
ds =
Surf
10
100
10
1000
1e+05
1
1
10000
>> ds.Surf = ordinal(ds.Surf,{'F' 'R' 'A' 'B' 'C' 'D'},[1 10 100 1000 10000 100000])
ds =
Surf
R
A
R
B
D
F
F
C
You can now do things like
>> ds(ds.Surf < 'A',:)
ans =
Surf
R
R
F
F
where Surf is created so that F<R<A<B<C<D (which may or my not be what you want).
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