load columns from file with headlines and dates

1 次查看（过去 30 天）
Ana
Ana 2013-4-23
date, Value(1) , Value(2) , Value(3) , Value(4) ........,Value(200)
date, ?, ?, ?, ?
2010/10/01 00:00:00, 0 , 0 , 0 , 0 ,....
2010/10/01 01:00:00, 12, 5.4, 0 , 0 ,....
2010/10/01 02:00:00, 7.6, 3.99, 1.18, 0 ,...
2010/10/01 03:00:00, 4.06, 0.0008, 4.05, 6.84,...
2010/10/01 04:00:00, 1.44, 0.0020, 4.096, 8.14,...
Hi!
I have a file like the one above (with headers and dates on the first column). With few columns I'm opening it with importfile('myfile.csv');
However I want to load only from, for example, column 100 to column 101. Any suggestions? I was trying with: dlmread('myfile',',','headlines',2) but doesnt work
Thanks

请先登录，再回答此问题。

回答（2 个）

Chandrasekhar
Chandrasekhar 2013-4-23
it can be read by using csvread command of matlab
  2 个评论
Ana
Ana 2013-4-23
It's not working. the file has headlines and the first column of the files are dates...
Matt Kindig
Matt Kindig 2013-4-23
编辑：Matt Kindig 2013-4-23
I think this should work using textread():
Format = ['%*s %*s ', repmat('%*f', [1 98]), '%f %f', '%*[\n]'];
data = textread('/path/to/your/file.csv', Format, 'delimiter', ',', 'headerLines', 2);

请先登录，再进行评论。

Cedric
Cedric 2013-4-23
编辑：Cedric 2013-4-23
Assuming that the date/time column has always the same format, the first value starts at char 22 and you can do something like:
cols = [100, 101] ;
buffer = zeros(1e6, length(cols)) ; % Prealloc for 1e6 entries.
fid = fopen('myFile.csv', 'r') ;
lCnt = 0 ;
while (~feof(fid))
line = fgetl(fid) ;
if line(1) == 'd', continue ; end % Skip lines starting with 'd'.
lCnt = lCnt + 1 ;
values = textscan(line(22:end), '%f,', Inf) ;
buffer(lCnt,:) = values{1}(cols) ;
end
fclose(fid) ;
buffer = buffer(1:lCnt,:) ; % Truncate to number of records.
Note that you might want to realloc buffer when lCnt hits 1e6 (or whichever value you are using for the prealloc). Also, a TEXTREAD guru could probably do this in one shot using this function.

类别

在 Help Center 和 File Exchange 中查找有关 Variables 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by