error message 'char'.how to solve?

Question

md sazzad 2023-4-19

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1949773-error-message-char-how-to-solve

评论： Walter Roberson 2023-4-25

function [EPClist,data]=extraction_data(Nomfichier)
dummy=importfile(Nomfichier);
j=1;
for i=1:height(dummy)
    if dummy.OperationResult(i)==' Read OK'
        data_raw(j,1)=dummy.Date(i);
        data_raw(j,2)=dummy.EPC(i);
        data_raw(j,3)=dummy.ReadData(i);
        j=j+1;
    end
end
clear dummy
EPClist=unique(data_raw(:,2));
Nb_capteur=length(EPClist);
data=cell(1,Nb_capteur);
for i=1:Nb_capteur
    k=1;
    for j=1:length(data_raw)
        if data_raw(j,2)==EPClist(i)
            %data{i}(k,1)=data_raw(j,1);
            %data{i}(k,1)=0;
            data{i}(k,1)=hex2dec(data_raw{j,3}(5:8));
            temphexa=data_raw{j,3}(9:12);
            if temphexa(1)=='F'
                data{i}(k,2)=1/100*(hex2dec(temphexa)-hex2dec('FFFF')+1);
            else
                data{i}(k,2)=1/100*hex2dec(temphexa);
            end
            k=k+1;
        end
    end 
    EPClist{i}=EPClist{i}(end-3:end);
end

Error message:

Undefined function 'importfile' for input arguments of type 'char'.

Error in extraction_data (line 3)

dummy=importfile(Nomfichier);

Error in detect_palier (line 3)

[EPC,B]=extraction_data(titre);

Error in extract_palier (line 23)

[EPC,pression,temperature]=detect_palier(titre,table_delete);

1 个评论
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Luca Ferro 2023-4-19

importfile is not a matlab built-in function, could you share its code or where you have taken it from?

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Answer 1

Walter Roberson 2023-4-19

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1949773-error-message-char-how-to-solve#answer_1219203

The function importdata has an option to generate a function that will import other files using the same configuration. It is common for the generated function to be called importfile . But it is not part of MATLAB; it is the result of someone using importdata() and asking to save the associated code.

These days, looking at the imported data, you should probably instead use readtable

6 个评论
显示 4更早的评论隐藏 4更早的评论

Walter Roberson 2023-4-24

在 MATLAB Online 中打开

Rewriting to use readtable:

function [EPClist,data]=extraction_data(Nomfichier)
dummy = readtable(Nomfichier);
j=1;
for i=1:height(dummy)
    if strtrim(dummy.OperationResult(i)) == "Read OK"
        data_raw(j,1)=dummy.Date(i);
        data_raw(j,2)=dummy.EPC(i);
        data_raw(j,3)=dummy.ReadData(i);
        j=j+1;
    end
end
clear dummy
EPClist=unique(data_raw(:,2));
Nb_capteur=length(EPClist);
data=cell(1,Nb_capteur);
for i=1:Nb_capteur
    k=1;
    for j=1:length(data_raw)
        if data_raw(j,2)==EPClist(i)
            %data{i}(k,1)=data_raw(j,1);
            %data{i}(k,1)=0;
            data{i}(k,1)=hex2dec(data_raw{j,3}(5:8));
            temphexa=data_raw{j,3}(9:12);
            if temphexa(1)=='F'
                data{i}(k,2)=1/100*(hex2dec(temphexa)-hex2dec('FFFF')+1);
            else
                data{i}(k,2)=1/100*hex2dec(temphexa);
            end
            k=k+1;
        end
    end 
    EPClist{i}=EPClist{i}(end-3:end);
end

This has three differences compared to your original:

changed importfile() to readtable()
changed ' Read OK' to "Read OK"
added strtrim()

I wanted to account for the possibility that when you used readtable() that possibly the leading space in ' Read OK' might not be present. Either way, whether it is or is not present, this code should work.

There is one potential problem, though: with readtable() the Date might be read as a datetime object rather than as numeric; if so then you would not be able to mix it in with numeric objects. But possibly it will come across as a char vector or as a cell array of char vectors or as a string... it would be easier if we had an extract of a file to test with.

md sazzad 2023-4-25

在 MATLAB Online 中打开

function [EPClist,data]=extraction_data(Nomfichier)
dummy = readtable(Nomfichier);
j=1;
for i=1:height(dummy)
    if strtrim(dummy.OperationResult(i)) == "Read OK"
        data_raw(j,1)=dummy.Date(i);
        data_raw(j,2)=dummy.EPC(i);
        data_raw(j,3)=dummy.ReadData(i);
        j=j+1;
    end
end
clear dummy
EPClist=unique(data_raw(:,2));
Nb_capteur=length(EPClist);
data=cell(1,Nb_capteur);
for i=1:Nb_capteur
    k=1;
    for j=1:length(data_raw)
        if data_raw(j,2)==EPClist(i)
            %data{i}(k,1)=data_raw(j,1);
            %data{i}(k,1)=0;
            data{i}(k,1)=hex2dec(data_raw{j,3}(5:8));
            temphexa=data_raw{j,3}(9:12);
            if temphexa(1)=='F'
                data{i}(k,2)=1/100*(hex2dec(temphexa)-hex2dec('FFFF')+1);
            else
                data{i}(k,2)=1/100*hex2dec(temphexa);
            end
            k=k+1;
        end
    end 
    EPClist{i}=EPClist{i}(end-3:end);
end