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 Kommentar
Azzi Abdelmalek
am 26 Dez. 2012
Bearbeitet: Azzi Abdelmalek
am 26 Dez. 2012
Is data a struct variable? (data.surf = 'F')
Akzeptierte Antwort
Teja Muppirala
am 27 Dez. 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 Kommentare
Teja Muppirala
am 27 Dez. 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)
Weitere Antworten (3)
Sean de Wolski
am 26 Dez. 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 Kommentare
Walter Roberson
am 27 Dez. 2012
If you are looking at data.surfs(K) then the new thing to write would be something like data.surfcodes(K)
Walter Roberson
am 26 Dez. 2012
letteridx = 1 + round(log10(data.surf);
letters = 'FRXUH';
data.surf = letters(letteridx);
2 Kommentare
Walter Roberson
am 27 Dez. 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
am 9 Jan. 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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