Read data with repeat counts

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Geetartha Dutta
Geetartha Dutta 2023-10-6
回答： Voss 2023-10-6
I have a data file containing numbers with repeat counts denoted by asterisk of the following format: 750.013 2*748.943 2*748.221 ... which is equivalent to 750.013 748.943 748.943 748.221 748.221 ... How can I read this data into a vector? That is, how can I take into account the repeat count operator (*) while reading the data?

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采纳的回答

Voss
Voss 2023-10-6
Ran in:
str = fileread('file.txt')
str = '750.013 2*748.943 2*748.221'
C = regexp(regexp(str,'\s+','split'),'\*','split');
idx = cellfun(@isscalar,C);
C(idx) = cellfun(@(x)[{'1'} x],C(idx),'UniformOutput',false);
M = str2double(vertcat(C{:}));
V = repelem(M(:,2).',M(:,1))
V = 1×5
750.0130 748.9430 748.9430 748.2210 748.2210

更多回答（2 个）

Mathieu NOE
Mathieu NOE 2023-10-6
Ran in:
hello
maybe this ?
data_string = "750.013 2*748.943 2*748.221"; % data imported as string array
data_string2 = split(data_string,' ');
%% main loop
store_value = [];
for k = 1:numel(data_string2)
tmp = char(data_string2(k));
ind = strfind(tmp,"*");
if ~isempty(ind) % we have 2*748.943 data (or alike
factor = str2num(tmp(1:ind-1));
value = str2num(tmp(ind+1:end));
value_all = repmat(value,[factor 1]);
store_value = [store_value;value_all];
else % we have a single value
store_value = [store_value;str2num(tmp)];
end
end
store_value
store_value = 5×1
750.0130 748.9430 748.9430 748.2210 748.2210
  1 个评论
Dyuman Joshi
Dyuman Joshi 2023-10-6
@Mathieu NOE, rather than growing the output dynamically, a better approach would be to preallocate according to the size of data_string2, find and store the number before asterisk for each element (if it does not exist, assign 1) and then use repelem on the unique elements.

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Les Beckham
Les Beckham 2023-10-6
Ran in:
Here is one approach.
data_strings = ["750.013"; "2*748.943"; "2*748.221"] % sample input data
data_strings = 3×1 string array
"750.013" "2*748.943" "2*748.221"
iData = 1;
for iStr = 1:numel(data_strings)
if contains(data_strings(iStr), "*")
tmp = split(data_strings(iStr), "*");
rpt = str2double(tmp(1));
data(iData:(iData + rpt - 1)) = str2double(tmp(2));
else
rpt = 1;
data(iData) = str2double(data_strings(iStr));
end
iData = iData + rpt;
end
disp(data)
750.0130 748.9430 748.9430 748.2210 748.2210

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