reding specific elements from .txt file

Hi

I want to read specific elements from .txt file. I am reading data from several files and they are having different no. of rows but same no. of columns. I want to read all the elements in 12th column and in rows which come after 10 the row.

So matrix which I am going to read will be a column matrix but of different length depending upon no. of rows in respective file.

[TAB]

Please give example of your data.

What is its content, number or string?

How columns are separated ?

[Nikhil CD]

All are numbers, delimiter is comma(,).

For example( I am assuming data of 6 columns and 8 rows)

1,2.5,45,-5,3.25,0,13,6

2.5,86,25,-4,0,0,12.5,2

2.1,-5,1.5,2.3,0,0,2.45,25

1,2.5,45,-5,0,0,1.23,6

2.5,86,25,-4,0,0,2.5,2

2.1,-5,1.5,2.3,0,0,0.45,25

In above case I need elements: 1.23,2.5,0.45

But in other files no of rows may be different and accordingly no of elements will vary.( in data of 8*8 i will input 5 elements(starting from row4))

[Nikhil CD]

Change in last sentence...(in data of 8*6 I will need elements 5 elements(starting from row4))

Answer 1

[TAB]

ReadCol=7;
ReadStartRow=4;

fh=fopen('test.txt');
txtcell=textscan(fh,'%s','delimiter','\n');
RowInFile=length(txtcell{1});

if(RowInFile<ReadStartRow)
    error('No of rows in text file are less than as expected by you.');
end

MyData=zeros(RowInFile-ReadStartRow+1,1);
R=1;
for ro=ReadStartRow:RowInFile
  Arr=cell2mat(textscan(txtcell{1}{ro},'%f','delimiter',','))';
  Mydata(R,1)=Arr(ReadCol);
  R=R+1;
end

Answer 2

[TAB]

StartRow=1;
EndRow=6;
StartCol=1;
EndCol=8;

if(StartRow>EndRow || StartCol>EndCol || any([StartRow  EndRow StartCol EndCol]==0))
    error('Indexing Error');
end

fh=fopen('YourFile.txt');
txtcell=textscan(fh,'%s','delimiter','\n');
if(length(txtcell{1})<EndRow)
    error('No of rows in text file are less than as expected by you.');
end

R=1;
MyData=zeros(EndRow-StartRow+1,EndCol-StartCol+1);
for i=StartRow:EndRow
  Arr=cell2mat(textscan(txtcell{1}{i},'%f','delimiter',','))';
  Mydata(R,:)=Arr(1,StartCol:EndCol);
  R=R+1;
end

[Nikhil CD]

I think I could not convey my problem to you properly.

I want to input all the elements in 7th column but starting from 4th row.

And also I am taking input from several files.

So depending upon the no. of rows in a file, no of elements to be read will be different.(Please note that no. of columns in all the files is same)

If file contains 9rows then I will read 6 elements(from 6th column and starting from 4th row)

If file contains 5 rows then I will read 2 elements(from 6th column and starting from 4th row)

[TAB]

Sorry for misunderstanding your need.

Please see my next answer.

I am again confused, either you want to read 7th column or 6th column. I am considering it 7th.

[Nikhil CD]

Yes. Its Ok..I got your logic. I can do further changes needed.

Thank you for your answer.