Read data with repeat counts

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?

Answer 1

[Voss]

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

Answer 2

[Mathieu NOE]

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

[Dyuman Joshi]

@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.

Answer 3

[Les Beckham]

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