I want to read data and variable name from txt file

The text file looks something like this and I want to create two coloumn one for value other for variable

DIM

CAP PF

FREQ MHz

IND NH

RES OHM

VAR

Lser = 0.4

Lser_Tx = 0.5

Qc =50

Ql = 50

Cshu= 1

Answer 1

[Voss]

For a text file that looks like that, readtable does essentially the right thing:

T = readtable('input_file_test.txt');

T.Properties.VariableNames = {'Variable','Value'}

T = 5×2 table
     Variable      Value
    ___________    _____

    {'Lser'   }     0.4 
    {'Lser_Tx'}     0.5 
    {'Qc'     }      50 
    {'Ql'     }      50 
    {'Cshu'   }       1 

[Aakriti Srivastava]

Thanks Voss,

But I have some quetions:

1. Before when I tried to store my data in a variable it starts to read the whole text file starting from DIM string. So, how this T.Properties.VariableName instruct the MATLAB to read and store data from 'VAR' string.

2. I have the full lenght text file which have variable name, numbers, special character and I want to sort and store data to make it easier for my functions retrive stored data and perform manipulation. So. would you please let me know is there any documnet which instruct to read text file. Because in MATLAB when i search for instruction to read text file it shows some instruction and it wont serve my purpose.

Thanks again for your help! Appreciated

[Voss]

1. T.Properties.VariableName doesn't control how the file is read. (It only controls what the variables are called in the resulting table T.) The difference between what I got here and what you got before must be due to using different files and/or using different code to read the files. Maybe share your actual file and/or the code you used before, in order to find out why the results are different.

2. There are many many functions that can read text files: readtable, readcell, readmatrix, fscanf, textscan, fread, etc. In order for me to figure out the best approach to read files of your particular format, it will be necessary for you to upload at least one such file (using the paperclip button).

[Aakriti Srivastava]

I have attached the file hope it may help and the code that I use to read is as follows.

fid = uigetfile();

a = fopen(fid);

b = fscanf(a,'%s %f')

[Voss]

If all you need is the section between the VAR line and the CKT line, here's one way to do it:

fid = fopen('text_file.txt');
data = fread(fid,'*char').';
fclose(fid);

start_idx = strfind(data,'VAR');
end_idx = strfind(data,'CKT');

C = strsplit(data(start_idx(1)+3:end_idx(1)-1),{'=' '\n' '\r'});
C = strtrim(reshape(C(2:end-1),2,[]).')

C = 7×2 cell array
    {'Lser'   }    {'0.4'}
    {'Lser_Tx'}    {'0.4'}
    {'QC'     }    {'70' }
    {'QL'     }    {'60' }
    {'Lshu'   }    {'4'  }
    {'fQ'     }    {'250'}
    {'Cshu'   }    {'1'  }

Now you have a cell array C containing the text from that section in two columns.

If you want that second column to be numeric you can do this:

C_cell = C;
C_cell(:,2) = num2cell(str2double(C_cell(:,2)))

C_cell = 7×2 cell array
    {'Lser'   }    {[0.4000]}
    {'Lser_Tx'}    {[0.4000]}
    {'QC'     }    {[    70]}
    {'QL'     }    {[    60]}
    {'Lshu'   }    {[     4]}
    {'fQ'     }    {[   250]}
    {'Cshu'   }    {[     1]}

And if you want the final result to be a table, you can do this:

C_table = cell2table(C_cell,'VariableNames',{'Variable' 'Value'})

C_table = 7×2 table
     Variable      Value
    ___________    _____

    {'Lser'   }     0.4 
    {'Lser_Tx'}     0.4 
    {'QC'     }      70 
    {'QL'     }      60 
    {'Lshu'   }       4 
    {'fQ'     }     250 
    {'Cshu'   }       1 

[Aakriti Srivastava]

Thank you so much Voss! It worked the way I want. :)

[Voss]

Excellent! You're welcome!

[Aakriti Srivastava]

May I know how you thought about such useful functions like strsplit amd strtrim because I may need few other as well to read section between 'CKT' and 'SUBCKT' of the file I shared.

[Voss]

Most functions have a "See Also" section at the end of their documentation page, which contains links to other related functions that may be useful:

https://www.mathworks.com/help/matlab/ref/strsplit.html#btnav5t_seealso

https://www.mathworks.com/help/matlab/ref/strtrim.html#bu8cvc2_seealso

[Aakriti Srivastava]

Thank you :)