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

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Padmamalini T H 2020-1-23

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https://ww2.mathworks.cn/matlabcentral/answers/501609-how-to-read-a-really-large-lines-of-data-ascii-file-format-to-a-table

评论： Walter Roberson 2020-4-7

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

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Allen 2020-1-25

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?

Padmamalini T H 2020-4-6

It has got headers. The datas are space seperated

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采纳的回答

Walter Roberson 2020-1-25

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https://ww2.mathworks.cn/matlabcentral/answers/501609-how-to-read-a-really-large-lines-of-data-ascii-file-format-to-a-table#answer_412026

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};

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Kavya Vuriti 2020-4-3

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.