how to use the str2num for the whole array at once

Dear all, when I read a text file and import it as an array A, sometimes I use the function str2num to return the imported vectors into a numerical form, but I need to do it for each vector alone. is there anyway please to reshape the whole array A into a numeric matrix at one time? like can i use the str2num to the whole matrix A and call it B for example?

thank you

[per isakson]

• "array A" is that a cell array?
• Could you provide a tiny example?
• Why import a text file with numerical data into character data and convert to numerical in a second step?

[MAHMOUD ALZIOUD]

I import data from a text file and gives me an array of 300000x105 dimension. i use this code

directory=dir('*.Y07');
count=0;
for K = 1 : length(directory)
    filename = directory(K).name;
    fileID = fopen(filename,'r');
    formatSpec = '%s';
    A_cell = textscan(fileID,formatSpec);
    A=char(A_cell{1,1}{:,:});
    A(find(A==nan))=0;
    %     y=A;
    [rows,columns]=size(A);

[Stephen23]

@MAHMOUD ALZIOUD: why do you use char? What is the file format? Is the file data string, numeric, or mixed?

It would be most useful if you uploaded a sample file for us to work with: add a comment and click the paperclip button. The sample file does not need to be the full file, just enough to be representative of the file format.

[MAHMOUD ALZIOUD]

Thank you Mr Steph, I import data from a text file that is must be divided into columns using the fixed width inputs. the output data is called A and it is a character of a size 300000x105. I have a problem here that the first line must be 105 characters but in matlab when i import the file it just takes the first 93. can i please pre-determine the matrix dimension before i import?

[Stephen23]

@MAHMOUD ALZIOUD: please make a new comment and upload a sample file by clicking the paperclip button.

We cannot run code using a screenshot, and no one is going to copy all that data from your screenshot. Screenshots are useless for doing anything with.

[MAHMOUD ALZIOUD]

I am trying to do so but the file is too large, the code i am using to import and divide data is this, note that it must be 105 characters in the columns but it just imports 93! how can i send you the text file please?

clear;
clc;

directory=dir('*.Y07');
count=0;

for K = 1 : length(directory)
    filename = directory(K).name;
    fileID = fopen(filename,'r');
    formatSpec = '%s';
    A_cell = textscan(fileID,formatSpec);
    A=char(A_cell{1,1}{:,:});
    A(find(A==nan))=0;

      A(isspace(A)) = '0';
      [rows,columns]=size(A);

      x1=filename;
      xtr=strcat('C:\Users\maa285\Desktop\New folder (2)\',x1);
      fid = fopen( xtr, 'wt' );

      Record_Type = A(:,1:1);
      FibsCode = A(:,2:3);
      StationID = A(:,4:9);
      Direction_Of_Travel = A(:,10:10);
      Lane_Of_Travel = A(:,11:11);
      Year_of_Data = A(:,12:13);
      Month_of_Data = A(:,14:15);
      Day_of_Data = A(:,16:17);
      Hour_of_Data = A(:,18:19);
      Vehicle_Class = A(:,20:21);
      Open = A(:,22:24);
      Total_Weight_of_vehicle = A(:,25:28);
      Number_of_axles = A(:,29:30);
      A_Axle_Weight = A(:,31:33);
      A_B_Axle_spacing = A(:,34:36);
      B_Axle_Weight = A(:,37:39);
      B_C_Axle_spacing = A(:,40:42);
      C_Axle_Weight = A(:,43:45);
      C_D_Axle_spacing = A(:,46:48);
      D_Axle_Weight = A(:,49:51);
      D_E_Axle_spacing = A(:,52:54);
      E_Axle_Weight = A(:,55:57);
      E_F_Axle_spacing = A(:,58:60);
      F_Axle_Weight = A(:,61:63);
      F_G_Axle_spacing= A(:,64:66);
      G_Axle_Weight = A(:,67:69);
      G_H_Axle_spacing = A(:,70:72);
      H_Axle_Weight = A(:,73:75);
      H_I_Axle_spacing = A(:,76:78);
      I_Axle_Weight= A(:,79:81);
      I_J_Axle_spacing = A(:,82:84);
      J_Axle_Weight = A(:,85:87);
      J_K_Axle_spacing= A(:,88:90);
      K_Axle_Weight = A(:,91:93);
      K_L_Axle_spacing = A(:,94:96);
      L_Axle_Weight = A(:,97:99);
      L_M_Axle_spacing = A(:,100:102);
      M_Axle_Weight = A(:,103:105);
      end

[MAHMOUD ALZIOUD]

this is a a sample of the data

[per isakson]

"note that it must be 105 characters in the columns"

• The longest row of NewTextDocument.txt is 57 characters.
• Does that mean that the rows shall be padded with space?
• "Open = A(:,22:24)" those columns contains space
• "xxxxx_spacing" What kind of variables are those that contain "spacing" in their names?

[Stephen23]

@MAHMOUD ALZIOUD: can you tell us something about the file format? Note that the answer to your original question would be to simply load all of that numeric data as numeric data. There is absolutely no point in loading it as strings and then converting to numeric.

[MAHMOUD ALZIOUD]

FOR Mr Per Note: I have 12 cards (or files), each card covers a month. but they do not have the same length in columns, some rows may or will have less than 105 characters, but the max length should be 105 as divided in the code above. the open field yes it has spaces and i need to fill the whole blanks with zeros. the spacing means the distance in inches between axles, they are numeric numbers. for example, if i have a row that is 66 character in length, i must fill the rest with zeros in it until i reach 105 characters for each row.

****************

Mr Steph, the file extension is called Y07 and it is ascii file i believe with text format. what is the best way to handle this file?

[per isakson]

• With releases older than R2017a (see Walters answer) you have to use an approach similar to your code.
• Which release do you use?
• The sizes of the intermediate variables are less than 100MB, thus the entire file may be read into memory. What's the size of your RAM?

[MAHMOUD ALZIOUD]

i have older than what Mr Walter said, i am sorry

[MAHMOUD ALZIOUD]

I have an 8 giga ram

Answer 1

[per isakson]

"I have older than what Mr Walter said" Thus the old way

Read the file and convert the content to an old time string array, str

    fid = fopen( 'NewTextDocument.txt' );
    cac = textscan( fid, '%s', 'Delimiter', '\n' );
    fclose( fid );
    str = char( cac{1} );
    str( str==' ' ) = '0';

Inspect str

>> whos str
  Name       Size             Bytes  Class    Attributes
  str       50x105            10500  char

and

>> str(1,:)
  ans = W39000779310707010002000001802010029008000000000000000000000000000000000000000000000000000000000000000000

Now you have a string array with the width of the longest row. The function, char, padded with space, which I replaced by the character '0'. (I padded one line of the text file with "0" up till the column 105.)

Now convert columns of the character array to numerical column vectors

Vehicle_Class = str2num( str(:,20:21) );
D_Axle_Weight = str2num( str(:,49:51) );

and inspect the result

>> whos Vehicle_Class D_Axle_Weight
  Name                Size            Bytes  Class     Attributes
  D_Axle_Weight      50x1               400  double              
  Vehicle_Class      50x1               400  double

With these pieces of code I think you can make your script work.

[MAHMOUD ALZIOUD]

Thank you very much Mr Per, this is very very helpful and great. I appreciate your help Sir.

[MAHMOUD ALZIOUD]

really thank you for your time and effort, this is amazing Sir

Answer 2

[Nicolas Schmit]

How about this?

A = {'1', '2', '3'}
B = cellfun(@str2num, A)

[MAHMOUD ALZIOUD]

This looks awsome man, I will use it and let you know what happens. thank you very much

[MAHMOUD ALZIOUD]

Hi Nicolas, I tried it and gave me this message: Input #2 expected to be a cell array, was char instead.

Answer 3

[Walter Roberson]

You have fixed width fields. You should see https://www.mathworks.com/help/matlab/ref/fixedwidthimportoptions.html if you have R2017a or later.

[MAHMOUD ALZIOUD]

Yes I am reading through this thank you, I think the problem is in my files, because they are not rectangular and each row does not have the same dimensions of the rest. I could open it, read it and divide it but the thing is it is not going beyond character 93, while i need it to reach 105