load text file

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Baba
Baba 2011-11-3
I have a text file that is too large to load with the file=load'file.txt' command. it's basically many rows of numbers where each column separated by a space.
1 2 3 1 4 2 1 56 2....
1 4 1 56 2 3 4 2 3 ....
....
Each row contains data from several channels. So for instance data from channel 1 would be 1 2 3 1 4 1, first 3 numbers of every line:
What I'd like to do is to filter and downsample data from each channel.
so basically I'm wondering what command is best to use to pick out specific parts of text file without using "load"
  1 个评论
Fangjun Jiang
Fangjun Jiang 2011-11-3
How large is the file? How many rows and columns?

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采纳的回答

Walter Roberson
Walter Roberson 2011-11-3
samplesperchan = 3;
channelnum = 6; %for example
lineformat = [repmat('%*f', 1, samplesperchan*(channelnum-1)), repmat('%f',1,samplesperchan), '%*[^\n]'];
result = textscan(fid, lineformat, 'CollectOutput', 1);
  8 个评论
Baba
Baba 2011-11-3
I'm getting an error:
??? Error using ==> textscan
Buffer overflow (bufsize = 4095) while reading string from
file (row 1, field 10). Use 'bufsize' option. See HELP
TEXTSCAN.
Error in ==> Untitled5 at 8
result = textscan(fid, lineformat, 'CollectOutput', 1);
and buffsize maximum size is 4095 bytes
is there a workaround that you know of?
Walter Roberson
Walter Roberson 2011-11-4
It sounds as if you might need to use 'bufsize' with a large number -- as large as your longest line.

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更多回答(1 个)

Ora Zyto
Ora Zyto 2011-11-3
Depending on the format of your data, TEXTSCAN may be a good option. This is a very flexible function, where you can specify the format of your data programatically.
You could read lines one by one and parse the data directly. If your data is rectangular, you could also try reading it all at once.
Ora

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