Sponsored Content
Top Forums Shell Programming and Scripting Determining number of overlaps between two files using Hashes? Post 302236347 by jim mcnamara on Monday 15th of September 2008 10:25:04 AM
Old 09-15-2008
Are there any other comparisons or output expectations you have not mentioned - because you maybe thought they did not matter?

Hashing is meant for a lookup for a match, not necessarily finding something numerically in a range or something that falls in between two values.


The first thing you must do is to undo the complexity of the line structures and then sort them if you want the process to complete in reasonable time.

I don't want to try anything until I'm sure we won't get into a feedback loop: 'Now I need this...'
 

10 More Discussions You Might Find Interesting

1. Programming

determining the object files...

hello, is there a utility to determine which object files are used to create a binary executable file?let me explain, please: for ex. there are three files: a.o b.o c.o and these files are used to create a binary called: prg namely, a.o b.o c.o -> prg so, how can i determine these three... (1 Reply)
Discussion started by: xyzt
1 Replies

2. Shell Programming and Scripting

Perl Hashes, reading and hashing 2 files

So I have two files that I want to put together via hashes and am having a terrible time with syntax. For example: File1 A apple B banana C citrusFile2 A red B yellow C orangeWhat I want to enter on the command line is: program.pl File1 File2And have the result... (11 Replies)
Discussion started by: silkiechicken
11 Replies

3. Shell Programming and Scripting

Creating Hashes of Hashes of Array

Hi folks, I have a structure as mentioned below in a configuration file. <Component> Comp1: { item1:data,someUniqueAttribute; item2:data,someUniqueAttribute, } Comp2: { item3:data,someUniqueAttribute; ... (1 Reply)
Discussion started by: ckv84
1 Replies

4. UNIX for Dummies Questions & Answers

Determining file size for a list of files with paths

Hello, I have a flat file with a list of files with the path to the file and I am attempting to calculate the filesize for each one; however xargs isn't playing nicely and I am sure there is probably a better way of doing this. What I envisioned is this: cat filename|xargs -i ls -l {} |awk... (4 Replies)
Discussion started by: joe8mofo
4 Replies

5. Shell Programming and Scripting

awk? create similarity matrix by calculating overlaps between sets comprising of individual parts

Hi everyone I am very new at awk and to me the task I need to get done is very very challenging... Nevertheless, after admiring how fast and elegant issues are being solved here I am sure this is my best chance. I have a 2D data file (input file is a plain tab-delimited text file). The first... (1 Reply)
Discussion started by: stonemonkey
1 Replies

6. Shell Programming and Scripting

Compare values of hashes of hash for n number of hash in perl without sorting.

Hi, I have an hashes of hash, where hash is dynamic, it can be n number of hash. i need to compare data_count values of all . my %result ( $abc => { 'data_count' => '10', 'ID' => 'ABC122', } $def => { 'data_count' => '20', 'ID' => 'defASe', ... (1 Reply)
Discussion started by: asak
1 Replies

7. Red Hat

Crontab: overlaps

I'm using CentOS 6.3 and I use a crontab entries like this: 0 23 2-31 * 1-6 root weekdayscript 0 23 1 * 7 root weekendscript this 2 entries always overlaps... but I don't know how... :wall: thanks (10 Replies)
Discussion started by: ionral
10 Replies

8. Shell Programming and Scripting

How to count number of files in directory and write to new file with number of files and their name?

Hi! I just want to count number of files in a directory, and write to new text file, with number of files and their name output should look like this,, assume that below one is a new file created by script Number of files in directory = 25 1. a.txt 2. abc.txt 3. asd.dat... (20 Replies)
Discussion started by: Akshay Hegde
20 Replies

9. Solaris

Determining number of hard disks in the system

Hello to all, what is the command in Solaris/Unix which I can use to determine how many hard disks exist in the system? I have tried with different command such as df -lk and similar but cannot know for sure how many actual disks are installed. Commands like # fdisk -l | grep Disk and #... (14 Replies)
Discussion started by: Mick
14 Replies

10. Shell Programming and Scripting

Base64 conversion in awk overlaps

hi, problem: output is not consistent as expected using external command in AWK description: I'm trying to convert $2 into a base64 string for later decoding, and for this when I use awk , I'm getting overlapped results , or say it results are not 100% correct. my code is: gawk... (9 Replies)
Discussion started by: busyboy
9 Replies
sort(3pm)						 Perl Programmers Reference Guide						 sort(3pm)

NAME
sort - perl pragma to control sort() behaviour SYNOPSIS
use sort 'stable'; # guarantee stability use sort '_quicksort'; # use a quicksort algorithm use sort '_mergesort'; # use a mergesort algorithm use sort 'defaults'; # revert to default behavior no sort 'stable'; # stability not important use sort '_qsort'; # alias for quicksort my $current; BEGIN { $current = sort::current(); # identify prevailing algorithm } DESCRIPTION
With the "sort" pragma you can control the behaviour of the builtin "sort()" function. In Perl versions 5.6 and earlier the quicksort algorithm was used to implement "sort()", but in Perl 5.8 a mergesort algorithm was also made available, mainly to guarantee worst case O(N log N) behaviour: the worst case of quicksort is O(N**2). In Perl 5.8 and later, quicksort defends against quadratic behaviour by shuffling large arrays before sorting. A stable sort means that for records that compare equal, the original input ordering is preserved. Mergesort is stable, quicksort is not. Stability will matter only if elements that compare equal can be distinguished in some other way. That means that simple numerical and lexical sorts do not profit from stability, since equal elements are indistinguishable. However, with a comparison such as { substr($a, 0, 3) cmp substr($b, 0, 3) } stability might matter because elements that compare equal on the first 3 characters may be distinguished based on subsequent characters. In Perl 5.8 and later, quicksort can be stabilized, but doing so will add overhead, so it should only be done if it matters. The best algorithm depends on many things. On average, mergesort does fewer comparisons than quicksort, so it may be better when complicated comparison routines are used. Mergesort also takes advantage of pre-existing order, so it would be favored for using "sort()" to merge several sorted arrays. On the other hand, quicksort is often faster for small arrays, and on arrays of a few distinct values, repeated many times. You can force the choice of algorithm with this pragma, but this feels heavy-handed, so the subpragmas beginning with a "_" may not persist beyond Perl 5.8. The default algorithm is mergesort, which will be stable even if you do not explicitly demand it. But the stability of the default sort is a side-effect that could change in later versions. If stability is important, be sure to say so with a use sort 'stable'; The "no sort" pragma doesn't forbid what follows, it just leaves the choice open. Thus, after no sort qw(_mergesort stable); a mergesort, which happens to be stable, will be employed anyway. Note that no sort "_quicksort"; no sort "_mergesort"; have exactly the same effect, leaving the choice of sort algorithm open. CAVEATS
As of Perl 5.10, this pragma is lexically scoped and takes effect at compile time. In earlier versions its effect was global and took effect at run-time; the documentation suggested using "eval()" to change the behaviour: { eval 'use sort qw(defaults _quicksort)'; # force quicksort eval 'no sort "stable"'; # stability not wanted print sort::current . " "; @a = sort @b; eval 'use sort "defaults"'; # clean up, for others } { eval 'use sort qw(defaults stable)'; # force stability print sort::current . " "; @c = sort @d; eval 'use sort "defaults"'; # clean up, for others } Such code no longer has the desired effect, for two reasons. Firstly, the use of "eval()" means that the sorting algorithm is not changed until runtime, by which time it's too late to have any effect. Secondly, "sort::current" is also called at run-time, when in fact the compile-time value of "sort::current" is the one that matters. So now this code would be written: { use sort qw(defaults _quicksort); # force quicksort no sort "stable"; # stability not wanted my $current; BEGIN { $current = print sort::current; } print "$current "; @a = sort @b; # Pragmas go out of scope at the end of the block } { use sort qw(defaults stable); # force stability my $current; BEGIN { $current = print sort::current; } print "$current "; @c = sort @d; } perl v5.12.1 2010-04-26 sort(3pm)
All times are GMT -4. The time now is 01:45 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy