Need to Generate Unique String

EchoAngel has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Need to Generate Unique String by Joost (Canon) on Jul 29, 2004 at 12:27 UTC
Try Data::Uniqid or UUID. "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply]
Re: Need to Generate Unique String by adrianh (Chancellor) on Jul 29, 2004 at 12:27 UTC
You might want to consider using Data::UUID.	[reply]
Re: Need to Generate Unique String by inman (Curate) on Jul 29, 2004 at 12:32 UTC
Take a look at Data::UUID. From the POD: This module provides a framework for generating UUIDs (Universally Unique Identifiers, also known as GUIDs (Globally Unique Identifiers). A UUID is 128 bits long, and is guaranteed to be different from all other UUIDs/GUIDs generated until 3400 CE.	[reply]
Re: Need to Generate Unique String by borisz (Canon) on Jul 29, 2004 at 12:25 UTC
Perhaps `gettimeofday` is enough. `perl -MTime::HiRes -le 'print join "",Time::HiRes::gettimeofday for (1 +..10)' __OUTPUT__ 1091103638899022 1091103638899336 1091103638899454 1091103638899566 1091103638899679 1091103638899787 1091103638899897 1091103638900006 1091103638900115 1091103638900239` [download] Boris	[reply] [d/l] [select]
Re: Need to Generate Unique String by eserte (Deacon) on Jul 29, 2004 at 12:18 UTC
With Time::HiRes::gettimeofday you have microseconds resolution.	[reply]
Re: Need to Generate Unique String by ccn (Vicar) on Jul 29, 2004 at 12:33 UTC
Simple solution: `$unique = time() . $$ . rand;`	[reply] [d/l]
Re^2: Need to Generate Unique String by tachyon (Chancellor) on Jul 29, 2004 at 12:57 UTC
`$uniquish = time() . $$ . rand;` ;-) cheers tachyon	[reply] [d/l]
Re^3: Need to Generate Unique String by stvn (Monsignor) on Jul 29, 2004 at 18:15 UTC
`use Digest::MD5; $pretty_darn_close_to_unique = md5_hex(md5_hex(time() . $$ . rand . {} +));` [download] -stvn	[reply] [d/l]
Re^4: Need to Generate Unique String by BrowserUk (Patriarch) on Jul 29, 2004 at 20:32 UTC
Re^5: Need to Generate Unique String by stvn (Monsignor) on Jul 29, 2004 at 22:24 UTC
Re^2: Need to Generate Unique String by hv (Prior) on Jul 29, 2004 at 19:58 UTC
You can get guaranteed uniqueness by replacing the rand call with a "hold this pid until the time changes": `$unique = time() . $$; sleep 1;` [download] Hugo	[reply] [d/l]
Re^3: Need to Generate Unique String by BrowserUk (Patriarch) on Jul 29, 2004 at 21:08 UTC
Guarenteed with a given process, but if multiple copies of the process are running, with time() limited to 1 second resolution? Examine what is said, not who speaks. "Efficiency is intelligent laziness." -David Dunham "Think for yourself!" - Abigail "Memory, processor, disk in that order on the hardware side. Algorithm, algoritm, algorithm on the code side." - tachyon	[reply]
Re^4: Need to Generate Unique String by hv (Prior) on Jul 30, 2004 at 12:13 UTC
Re^3: Need to Generate Unique String by ccn (Vicar) on Jul 29, 2004 at 20:04 UTC
Or use a counter: `{ my $cnt = 0; sub unique { return $time() . $$ . $cnt++; } } $unique = unique();` [download]	[reply] [d/l]
Re: Need to Generate Unique String by Jaap (Curate) on Jul 29, 2004 at 12:14 UTC
Do you have a chance to view all the other/previous UID's? Then take the higest one and ++ it.	[reply]