Read text file, identify variables and rewrite some of the variables

Question

shadman khan 2022-11-29

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1866703-read-text-file-identify-variables-and-rewrite-some-of-the-variables

编辑： shadman khan 2022-12-8

采纳的回答： Voss

Initial.txt

Hello.

I have a text file with its contents as shown below

A5Q00 0.30000000E+00 PMA: A, X, Y_i, Z 0.10000000E-16 0.10000000E-16 0.10000000E-16 0.30000000E+00

0.1045720000000E+08 0.1000000000000E-79 0.3500000000000E-01 0.2665390000000E+00

A5Q01 0.30000000E+00 PMB: P, X, B_i, T 0.10000000E-16 0.10000000E-16 0.10000000E-16 0.30000000E+00

0.1045720000000E+08 0.1000000000000E-79 0.3500000000000E-01 0.2665390000000E+00

A5Q02 0.30000000E+00 PMD: K, X, R_i, T 0.10000000E-16 0.10000000E-16 0.10000000E-16 0.30000000E+00

0.1045720000000E+08 0.1000000000000E-79 0.3500000000000E-01 0.2665390000000E+00

i want to store these variables V1, V2, V3...V15 for each element and change their values and again write these back to a .txt file.

I have tried using split string and storing these in the cells but i have failed ot write these cells to a text file.

clc

clear all

close all

fid =fopen('Initial.txt','r')

tline = fgetl(fid);

k = 1;

while ischar(tline)

%// Store in a cell array

A{k}=strsplit(tline," ")

tline = fgetl(fid);

k = k+1;

end

V1=A{1,1}{:,1}

V2=A{1,1}{:,2}

V3=A{1,1}{:,3}

V4=A{1,1}{:,4}

V5=A{1,1}{:,5}

V6=A{1,1}{:,6}

V7=A{1,1}{:,7}

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Answer 1

Voss 2022-11-29

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1866703-read-text-file-identify-variables-and-rewrite-some-of-the-variables#answer_1115418

编辑：Voss 2022-11-29

在 MATLAB Online 中打开

Initial.txt

% read the file into a char vector:
fid = fopen('Initial.txt');
data = fread(fid,'*char').';
fclose(fid);
disp(data);
A5Q00           0.30000000E+00  Aqu: P,     X_m_A, X_i_A, T             0.10000000E-16 0.10000000E-16 0.10000000E-16 0.30000000E+00
 0.1045720000000E+08 0.1000000000000E-79 0.3500000000000E-01 0.2665390000000E+00
A5Q01           0.30000000E+00  Aqu: P,     X_m_A, X_i_A, T             0.10000000E-16 0.10000000E-16 0.10000000E-16 0.30000000E+00
 0.1045720000000E+08 0.1000000000000E-79 0.3500000000000E-01 0.2665390000000E+00
A5Q02           0.30000000E+00  Aqu: P,     X_m_A, X_i_A, T             0.10000000E-16 0.10000000E-16 0.10000000E-16 0.30000000E+00
 0.1045720000000E+08 0.1000000000000E-79 0.3500000000000E-01 0.2665390000000E+00
% split into a cell array, reshape:
V = reshape(strsplit(data),15,[])
V = 15×3 cell array
    {'A5Q00'              }    {'A5Q01'              }    {'A5Q02'              }
    {'0.30000000E+00'     }    {'0.30000000E+00'     }    {'0.30000000E+00'     }
    {'Aqu:'               }    {'Aqu:'               }    {'Aqu:'               }
    {'P,'                 }    {'P,'                 }    {'P,'                 }
    {'X_m_A,'             }    {'X_m_A,'             }    {'X_m_A,'             }
    {'X_i_A,'             }    {'X_i_A,'             }    {'X_i_A,'             }
    {'T'                  }    {'T'                  }    {'T'                  }
    {'0.10000000E-16'     }    {'0.10000000E-16'     }    {'0.10000000E-16'     }
    {'0.10000000E-16'     }    {'0.10000000E-16'     }    {'0.10000000E-16'     }
    {'0.10000000E-16'     }    {'0.10000000E-16'     }    {'0.10000000E-16'     }
    {'0.30000000E+00'     }    {'0.30000000E+00'     }    {'0.30000000E+00'     }
    {'0.1045720000000E+08'}    {'0.1045720000000E+08'}    {'0.1045720000000E+08'}
    {'0.1000000000000E-79'}    {'0.1000000000000E-79'}    {'0.1000000000000E-79'}
    {'0.3500000000000E-01'}    {'0.3500000000000E-01'}    {'0.3500000000000E-01'}
    {'0.2665390000000E+00'}    {'0.2665390000000E+00'}    {'0.2665390000000E+00'}
% convert to numbers, where possible:
temp = str2double(V);
is_number = ~isnan(temp);
V(is_number) = num2cell(temp(is_number))
V = 15×3 cell array
    {'A5Q00'     }    {'A5Q01'     }    {'A5Q02'     }
    {[    0.3000]}    {[    0.3000]}    {[    0.3000]}
    {'Aqu:'      }    {'Aqu:'      }    {'Aqu:'      }
    {'P,'        }    {'P,'        }    {'P,'        }
    {'X_m_A,'    }    {'X_m_A,'    }    {'X_m_A,'    }
    {'X_i_A,'    }    {'X_i_A,'    }    {'X_i_A,'    }
    {'T'         }    {'T'         }    {'T'         }
    {[1.0000e-17]}    {[1.0000e-17]}    {[1.0000e-17]}
    {[1.0000e-17]}    {[1.0000e-17]}    {[1.0000e-17]}
    {[1.0000e-17]}    {[1.0000e-17]}    {[1.0000e-17]}
    {[    0.3000]}    {[    0.3000]}    {[    0.3000]}
    {[  10457200]}    {[  10457200]}    {[  10457200]}
    {[1.0000e-80]}    {[1.0000e-80]}    {[1.0000e-80]}
    {[    0.0350]}    {[    0.0350]}    {[    0.0350]}
    {[    0.2665]}    {[    0.2665]}    {[    0.2665]}
% ...
% make modifications to V, as desired
% ...
V{2,2} = 0.7 % (for example)
V = 15×3 cell array
    {'A5Q00'     }    {'A5Q01'     }    {'A5Q02'     }
    {[    0.3000]}    {[    0.7000]}    {[    0.3000]}
    {'Aqu:'      }    {'Aqu:'      }    {'Aqu:'      }
    {'P,'        }    {'P,'        }    {'P,'        }
    {'X_m_A,'    }    {'X_m_A,'    }    {'X_m_A,'    }
    {'X_i_A,'    }    {'X_i_A,'    }    {'X_i_A,'    }
    {'T'         }    {'T'         }    {'T'         }
    {[1.0000e-17]}    {[1.0000e-17]}    {[1.0000e-17]}
    {[1.0000e-17]}    {[1.0000e-17]}    {[1.0000e-17]}
    {[1.0000e-17]}    {[1.0000e-17]}    {[1.0000e-17]}
    {[    0.3000]}    {[    0.3000]}    {[    0.3000]}
    {[  10457200]}    {[  10457200]}    {[  10457200]}
    {[1.0000e-80]}    {[1.0000e-80]}    {[1.0000e-80]}
    {[    0.0350]}    {[    0.0350]}    {[    0.0350]}
    {[    0.2665]}    {[    0.2665]}    {[    0.2665]}
% write a new file with the modified V:
fid = fopen('Modified.txt','w');
fprintf(fid,'%-15s %14.8E  %-s %-s %10s %6s %-13s %14.8E %14.8E %14.8E %14.8E\n %19.13E %19.13E %19.13E %19.13E\n',V{:});
fclose(fid);
% view the new file's contents:
type Modified.txt
A5Q00           3.00000000E-01  Aqu: P,     X_m_A, X_i_A, T             1.00000000E-17 1.00000000E-17 1.00000000E-17 3.00000000E-01
 1.0457200000000E+07 1.0000000000000E-80 3.5000000000000E-02 2.6653900000000E-01
A5Q01           7.00000000E-01  Aqu: P,     X_m_A, X_i_A, T             1.00000000E-17 1.00000000E-17 1.00000000E-17 3.00000000E-01
 1.0457200000000E+07 1.0000000000000E-80 3.5000000000000E-02 2.6653900000000E-01
A5Q02           3.00000000E-01  Aqu: P,     X_m_A, X_i_A, T             1.00000000E-17 1.00000000E-17 1.00000000E-17 3.00000000E-01
 1.0457200000000E+07 1.0000000000000E-80 3.5000000000000E-02 2.6653900000000E-01

Instead of having numerous sequentially-numbered variables (V1, V2, V3, etc.) it's better to have a single variable that you can index (V(1), V(2), V(3), ..., or V{1}, V{2}, V{3}, ..., or V(1,:), V(2,:), V(3,:), ..., etc.)

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Voss 2022-12-4

Hi @shadman khan, I am unable to look into this in detail at the moment, so you may want to open a new question about this issue with the space in the parameter name, and link back to this question/thread.

shadman khan 2022-12-6

编辑：shadman khan 2022-12-8

Dear @Voss

here's th link o the new question. I hope you can take a look when you are available: https://in.mathworks.com/matlabcentral/answers/1871827-read-text-file-identify-variables-combine-some-the-variables-and-write-these-variables-to-another

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Answer 2

Steven Lord 2022-11-29

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1866703-read-text-file-identify-variables-and-rewrite-some-of-the-variables#answer_1115443

在 MATLAB Online 中打开

I'd probably read this into a table array. A first pass at reading in this file is below. You probably want to customize the import options (perhaps using the Import Tool, uiimport, to allow you to interactively explore the effect of different options.)

thefile = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/1212458/Initial.txt';

The file seems to be space delimited, but let's treat multiple spaces as one delimiter.

importOptions = detectImportOptions(thefile, 'Delimiter', ' ', ...
                                             'ConsecutiveDelimitersRule', 'join');

By default readtable takes the first row as the list of variable names, but the first row of your file is data. So let's specify some default names and say to read all the lines as data.

importOptions.VariableNames = "Var" + (1:numel(importOptions.VariableNames));
importOptions.DataLines = [1 Inf];

Now actually import the data.

T = readtable(thefile, importOptions)
T = 6×11 table
       Var1          Var2       Var3     Var4      Var5         Var6          Var7       Var8     Var9     Var10    Var11
    __________    __________    _____    _____    _______    __________    __________    _____    _____    _____    _____

    {'A5Q00' }           0.3      NaN      NaN        NaN    {'X_i_A,'}    {'T'     }    1e-17    1e-17    1e-17     0.3 
    {0×0 char}    1.0457e+07    1e-80    0.035    0.26654    {0×0 char}    {0×0 char}      NaN      NaN      NaN     NaN 
    {'A5Q01' }           0.3      NaN      NaN        NaN    {'X_i_A,'}    {'T'     }    1e-17    1e-17    1e-17     0.3 
    {0×0 char}    1.0457e+07    1e-80    0.035    0.26654    {0×0 char}    {0×0 char}      NaN      NaN      NaN     NaN 
    {'A5Q02' }           0.3      NaN      NaN        NaN    {'X_i_A,'}    {'T'     }    1e-17    1e-17    1e-17     0.3 
    {0×0 char}    1.0457e+07    1e-80    0.035    0.26654    {0×0 char}    {0×0 char}      NaN      NaN      NaN     NaN 

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shadman khan 2022-11-29

Hi Steven thanks for your reply. I like the compact code, but its not providing the few variables like Var3, Var4, etc.,

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Read text file, identify variables and rewrite some of the variables

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