MATLAB Answers

how to read a really large lines of data(ascii file format) to a table

6 views (last 30 days)
i have a really large ascii file that contains about 23,46,503 number of lines. i need to read them to a table with data types of each column as only text and number. i tried to import them using import data tool but it is taking forever to scan and parse the data (im using matlab 2019a). can anyone suggest me a faster approach to read the file to a table please. i even tried codes such as readtable(), dlmread(), fopen, fscanf etc. nothing works and it is throwing error.
it would be of great help if anyone helps

  6 Comments

Show 3 older comments
Padmamalini  T H
Padmamalini T H on 25 Jan 2020
Can i have the code to read an ascii file. Because When i give .asc it is showing error, when i give .txt or .dat(since the data is in a notepad) it shows error
Allen
Allen on 25 Jan 2020
Does the start of the data in your .txt file contain any header lines or does it explicitly contain data in the format you have provided? Also, is this data tab-delimited?

Sign in to comment.

Accepted Answer

Walter Roberson
Walter Roberson on 25 Jan 2020
filename = 'YourFile.txt':
[fid, msg] = fopen(filename);
if fid < 0
error('Failed to open file "%s" because "%s"', filename, msg);
end
%0.2120 1 CF00203x Rx d 8 00 00 00 FF FF 00 00 FF
fmt = ['%f%f%s%s', repmat('%x', 1, 10)];
datacell = textscan(fid, fmt, 'CollectOutput', true);
fclose(fid);
numeric_vals = [datacell{1}, datacell(3})];
text_vals = datacell{2};

  5 Comments

Show 2 older comments
Padmamalini  T H
Padmamalini T H on 30 Jan 2020
thanks now i have called the asc file into the matlab environment. but i wanted the ascii file in a table in the workspace.
Kavya Vuriti
Kavya Vuriti on 3 Apr 2020
You can try using importdata function to obtain structure containing data field and then use table function to convert it into table. As the file contains 23,46,503 number of lines, it takes around 1.66 seconds for importing.
Walter Roberson
Walter Roberson on 7 Apr 2020
i wanted the ascii file in a table in the workspace.
And what format is the table to be in?
You can use
array2table(numeric_vals)
and you can add in variables from text_vals{:,1} and text_vals{:,2} if you want a table() object.

Sign in to comment.

More Answers (0)

Tags