importing a column of data from a text file

i need to import a particular column of data from a text file. the columns are differentiated by the size of the numbers. For example :

20 30000

21 40000

24 50000

how can i do so?

Answer 1

[Azzi Abdelmalek]

Import the data using

data=dlmread('yourfilename.txt')

Then choose the column you want

data(:,2)

% You can get the sizes of numbers in each column

numbers=arrayfun(@(x) numel(num2str(x)),data(1,:))

[Siddharth]

but it can be the other way round too as in if the larger values are in the first column. i need to select the column with larger values.

[Azzi Abdelmalek]

data=dlmread('yourfilename.txt')
numbers=arrayfun(@(x) numel(num2str(x)),data(1,:))
[idx,idx]=max(numbers)
result=data(:,idx)

[Azzi Abdelmalek]

or simply

data=dlmread('yourfilename.txt')
[idx,idx]=max(data(1,:))
result=data(:,idx)

Answer 2

[Andrei Bobrov]

d = dlmread('yourtxtfile.txt');
[k,k] = max(log10(d(1,:)));
out = d(:,k);

or

[k,k] = max(log10(d(:)));
out = d(:,ceil(k/size(d,1)))