How to read the entire column of a file and save it in a variable?

Question

Hamza 2012-9-22

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/48830-how-to-read-the-entire-column-of-a-file-and-save-it-in-a-variable

Dear All I have the below text file (part of it).

 =====================================================================
1996-063A   ARABSAT-2B                                       
  Launched: 1996-11-13 (318)           Start Date: 1996-06-12 (164)  
   Decayed:                             Stop Date: 2003-12-20 (354)  
=====================================================================
24652U 96063A   96318.74847837 -.00000020  00000-0  00000+0 0    14
24652   3.9929 210.6007 7281127 177.7757 190.4436  2.27277888    06
24652U 96063A   96319.62211352 -.00000020  00000-0  00000+0 0    31
24652   3.9929 210.3183 7284735 178.4392 185.2995  2.27373269    12
24652U 96063A   96319.62351606  .00008082  00000-0  30835-2 0    24
24652   3.9764 210.1654 7280836 178.5436 186.6267  2.27380102    20
24652U 96063A   96319.62356237  .00009638  00000-0  38025-2 0    37
24652   3.9632 210.3512 7280110 178.4006 186.6625  2.27374993    25
24652U 96063A   96320.05952563 -.00002597  00000-0 -98092-3 0    63
24652   3.9623 210.1661 7275699 178.7092 185.6294  2.27896863    39
24652U 96063A   96320.49676119 -.00000127  00000-0  10000-4 0    72

I am using the following code to read the each line.

fid=fopen('2B.txt');
A=textscan(fid,'%s','HeaderLines',5);
Data=reshape(A{1}(1:end-3,:),9,[])';
fclose(fid);
l1=Data(1:2:end,:);
l2=Data(2:2:end,:);

I want to read all the elements of line 1 (l1) column 4(i.e. 96318.74847837, 96319.6221135296, and so on..)

I tried t=l1(:,4) but it doesn't work. It only displays 96318.74847837

please help.

2 个评论
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per isakson 2012-9-22

What is this "00000-0 00000+0"?

Hamza 2012-9-23

It's basically a TLE data(Two line element) and those '0's refer to drag term and 2nd derivative of mean motion.

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Answer 1

Azzi Abdelmalek 2012-9-22

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/48830-how-to-read-the-entire-column-of-a-file-and-save-it-in-a-variable#answer_59671

编辑：Azzi Abdelmalek 2012-9-22

在 MATLAB Online 中打开

fid=fopen('2B.txt');
A=textscan(fid,'%s','HeaderLines',5);
fclose(fid);
n=numel(A{:});
Data=reshape(A{1},9,[])';
l1=Data(1:2,:);
l2=Data(2:2,:);
t=l1(:,4:end)

%or using fgetl.

fid = fopen('2B.txt');
tline = fgetl(fid);
out=tline
while ischar(tline)
  tline = fgetl(fid);
  out=char(out,tline)
end
fclose(fid);
n=size(out,1);
res=[]
for k=6:n
r=regexp(out(k,:),' ','split')
r1=cell2mat(cellfun(@(x) ~isempty(x),r,'Uni',false))
r2=r(r1)
res=[res;cellfun(@(x) str2num(x),r2(4:end))]
end

3 个评论
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Azzi Abdelmalek 2012-9-23

It's not t=l(:,4) but t=l(:,4:end)

Hamza 2012-9-24

I was talking about my previous code that t=l1(:,4) is now displaying all the elements of 4th column. Which it wasn't displaying previously.

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Answer 2

bym 2012-9-22

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/48830-how-to-read-the-entire-column-of-a-file-and-save-it-in-a-variable#answer_59670

在 MATLAB Online 中打开

try using this

A=textscan(fid,repmat('%s',1,9),'HeaderLines',5);
>> A{4}(1:2:end)
ans = 
      '96318.74847837'
      '96319.62211352'
      '96319.62351606'
      '96319.62356237'
      '96320.05952563'
      '96320.49676119'