Read text file - ignoring lines starting with specific character.

Question

Billy 2019-10-1

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/483004-read-text-file-ignoring-lines-starting-with-specific-character

回答： Stephen23 2019-10-1

I have a text file with 17 columns of numeric data separated by a double space. These are preceded by some number of lines starting with the '#' symbol. I would like to discard all lines starting with '#' and only read the numeric data, but these numbers need to be read in as strings. How do I ignore all lines starting with '#' and only read the remaining lines as strings?

The text file is of the form (but with more columns):

# filename

# date and time

# some more info

1.111111111 2.222222222 3.333333333 4.444444444 ...

1.111111112 2.222222223 3.333333334 4.444444445 ...

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Jon 2019-10-1

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/483004-read-text-file-ignoring-lines-starting-with-specific-character#answer_394273

编辑：Jon 2019-10-1

I'm not sure why you would want to read in numerical data as strings.

You can read in the data in your files using (assuming for example your file is called myfile.csv)

A = readmatrix('myfile.csv','Delimiter',' ')

note that you seem to have two spaces between your values so it is ' ', not ' ' as the delimiter.

If you really want them to be strings, you can alway change them into strings after you read them in as numbers, using for instance

Astr = num2str(A)

If for some reason readmatrix is confused about some of the initial header lines (the ones you shouw starting with #, if you know how many header lines you can also specify that for example, for 3 header lines as you show in your listing

A = readmatrix('myfile.csv','Delimiter,' ',NumHeaderLines',3)

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Stephen23 2019-10-1

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/483004-read-text-file-ignoring-lines-starting-with-specific-character#answer_394276

test.txt

nmc = 4; % number of columns in file
fmt = repmat('%f',1,nmc);
opt = {'HeaderLines',3, 'CollectOutput',true, 'MultipleDelimsAsOne',true};
%
[fid,msg] = fopen('test.txt','rt');
assert(fid>=3,msg)
C = textscan(fid,fmt,opt{:});
fclose(fid);
M = C{1}

giving:

M =
   1.111111111000000   2.222222222000000   3.333333333000000   4.444444444000000
   1.111111112000000   2.222222223000000   3.333333334000000   4.444444445000000