HI
I have a hash like this
$hashname->{$filesystem}->{'fsname'}=$filesystem;
How to get the values from this multilevel hash.
Thanks in advance... :) (1 Reply)
print $hash{$value} if exists $hash{$key};
would only print my top value, and not the one I want to "match".... should i not be using if exists? how would you recommend "searching" a hash file...
thanks! (6 Replies)
Hi i am reading one file and creating Hash from the contents of it my issue is there are 3 different files in 3 different locations having same structure so for parsing these files i have one subroutine which returns hash after reading all the 3 files i need to create consolidated hash from three... (2 Replies)
Can Someone explain me why even using Tie::IxHash I can not get the output data in the same order that it was inserted? See code below.
#!/usr/bin/perl
use warnings;
use Tie::IxHash;
use strict;
tie (my %programs, "Tie::IxHash");
while (my $line = <DATA>) {
chomp $line;
my(... (1 Reply)
Hi,
In Perl, is it possible to use a range of numbers with '..' as a key in a hash?
Something in like:
%hash = (
'768..1536' => '1G',
'1537..2560' => '2G'
);
That is, the range operation is evaluated, and all members of the range are... (3 Replies)
Hi ,
i have the below code its working fine when i execute in unix , but its not working in windows could you pls explain me where i am going wrong.
This is the program
$data = { '1' => 'one' ,
'2' => 'two' ,
3 => 'three'
};
print "hello : $data->{'1'}... (2 Replies)
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)
My issue is that the perl script (as I have done it so far) created empty branches when I try to check some branches on existence.
I am using multydimentional hashes: found it as the best way for information that I need to handle. Saing multidimentional I means hash of hashes ... So, I have
... (2 Replies)
Discussion started by: alex_5161
2 Replies
LEARN ABOUT DEBIAN
bup-margin
bup-margin(1) General Commands Manual bup-margin(1)NAME
bup-margin - figure out your deduplication safety margin
SYNOPSIS
bup margin [options...]
DESCRIPTION
bup margin iterates through all objects in your bup repository, calculating the largest number of prefix bits shared between any two
entries. This number, n, identifies the longest subset of SHA-1 you could use and still encounter a collision between your object ids.
For example, one system that was tested had a collection of 11 million objects (70 GB), and bup margin returned 45. That means a 46-bit
hash would be sufficient to avoid all collisions among that set of objects; each object in that repository could be uniquely identified by
its first 46 bits.
The number of bits needed seems to increase by about 1 or 2 for every doubling of the number of objects. Since SHA-1 hashes have 160 bits,
that leaves 115 bits of margin. Of course, because SHA-1 hashes are essentially random, it's theoretically possible to use many more bits
with far fewer objects.
If you're paranoid about the possibility of SHA-1 collisions, you can monitor your repository by running bup margin occasionally to see if
you're getting dangerously close to 160 bits.
OPTIONS --predict
Guess the offset into each index file where a particular object will appear, and report the maximum deviation of the correct answer
from the guess. This is potentially useful for tuning an interpolation search algorithm.
--ignore-midx
don't use .midx files, use only .idx files. This is only really useful when used with --predict.
EXAMPLE
$ bup margin
Reading indexes: 100.00% (1612581/1612581), done.
40
40 matching prefix bits
1.94 bits per doubling
120 bits (61.86 doublings) remaining
4.19338e+18 times larger is possible
Everyone on earth could have 625878182 data sets
like yours, all in one repository, and we would
expect 1 object collision.
$ bup margin --predict
PackIdxList: using 1 index.
Reading indexes: 100.00% (1612581/1612581), done.
915 of 1612581 (0.057%)
SEE ALSO bup-midx(1), bup-save(1)BUP
Part of the bup(1) suite.
AUTHORS
Avery Pennarun <apenwarr@gmail.com>.
Bup unknown-bup-margin(1)