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Large file - columns into rows etc

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# 8  
Old 06-09-2010
No will not matter;Tabs are considered to be spaces (actually 8 spaces)

Smilie
# 9  
Old 06-09-2010
Array::Transpose Uses two Variables
if the first example I gave runs the box out of memory with only one array, using Array::Transpose should run the box out of memory twice as quickly, yes?

After a brief RTS A::T uses two named variables to do the lifting
# 10  
Old 06-09-2010
same code with modification where the max array (@in) size is equal to row size SmilieSmilieSmilie @in array of references:

Code:
#!/bin/perl -w

use Array::Transpose ;
open(FH,"<infile.txt") or die "something wrong $!" ;

while (<FH>) {
chomp $_ ;
push @in , [ split /\s+/ , $_  ] ;
}

END{
         foreach (transpose(\@in)) {
                  print "@{$_}\n" ;
	     }
}

SmilieSmilieSmilie
# 11  
Old 06-11-2010
Thanks!
I think this has worked. I'm still getting the "out of memory" and the same grep errors but when I count the rows and columns, they seem to be right.

Dunno how else to check whether the file has been sorted correctly, though, if I can't view it.
# 12  
Old 06-11-2010
The algorithm in Array::Transpose is better than the one I was working together, I would suggest using that. The out of memory error is still there because there is still a single array holding all the data at once.

One way around this problem is to break the run into smaller chunks of data

Code:
bash> head -100000 | tail -100000 | perl -e '....' > out.1
bash> head -200000 | tail -100000 | perl -e '....' > out.2
bash> head -300000 | tail -100000 | perl -e '....' > out.3
bash> head -400000 | tail -100000 | perl -e '....' > out.4
bash> head -500000 | tail -100000 | perl -e '....' > out.5

Then /bin/cat the out files together:

Code:
bash> cat out.1 out.2 out.3 out.4 out.5 > concattted.out

This will break the data in five more managable chunks. Let us know if you are still getting the "Out of Memory!" Error. you can always break the datafile into 50_000 line segments, and so on...

HTH,

Scott
# 13  
Old 06-11-2010
I will try this. One question though, which could be slightly stupid:

For example: head -100000 | tail -100000 | perl -e '....' > out.1

I know head -100000 = first 100000 lines of the file and
tail -100000 = last 100000 lines in the file...
but what lines are specified if you put both like you have done?
# 14  
Old 06-11-2010
Split Large file with 2
Quote:
Originally Posted by Myrona
what lines are specified if you put both like you have done?
You are correct that the first line is redundant, i.e. you could simply do this:

Code:
bash> head -100000 | perl -e '....' > out.1

I use this idiom frequently, and I like starting the pattern of pipelines in a way that can stay constant. It a preference thing.

you could also cat the first one
Last edited by deindorfer; 06-11-2010 at 12:40 PM..
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