Comparing Two Numbers

abs52 has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks, I am using version 0.77 to compare two numbers but it does not seems to be working as expected Here is the code

#!/usr/bin/env perl
use version 0.77;

my $wanted = '450.80.82';
my $installed = '450.57';

if (version->parse($installed) >= version->parse($wanted)) {
  INFO "$installed newer than or same as wanted ($wanted), not doing a
+nything\n";
  exit 0;
}
[download]

I would expect it to not going into the if loop as 450.80.82 is great than 450.87 Have i done something wrong Thanks

Comment on Comparing Two Numbers Download Code

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Re: Comparing Two Numbers by choroba (Cardinal) on Jan 05, 2021 at 09:43 UTC
Use numify to see what's under the hood: `print version->parse($installed)->numify, '<=>', version->parse($wante +d)->numify, "\n"; # Output: 450.570<=>450.080082` [download] Use 450.57.0 to get what you expect. Comparing dotted versions with different number of elements is tricky. `map{substr$_->[0],$_->[1]\|\|0,1}[\\|\|{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^ARGV,3]`	[reply] [d/l] [select]
Re^2: Comparing Two Numbers by abs52 (Novice) on Jan 05, 2021 at 10:03 UTC
Thanks, unfortunately i am comparing driver version, meaning that the numbers needs to correct. As i am using the code to determine if a driver is installed and or should we be installing a new version	[reply]
Re^3: Comparing Two Numbers by choroba (Cardinal) on Jan 05, 2021 at 10:07 UTC
What driver? If it's a Perl module, it got versioning wrong. If it's not, it might use a different versioning rules, which means you can't use Perl's version. `map{substr$_->[0],$_->[1]\|\|0,1}[\\|\|{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^ARGV,3]`	[reply] [d/l]
Re^4: Comparing Two Numbers by abs52 (Novice) on Jan 05, 2021 at 10:15 UTC
Re^3: Comparing Two Numbers by Ratazong (Monsignor) on Jan 05, 2021 at 11:07 UTC
Hello abs52 You could check if your two version strings both contain two dots - and append a ".0" if not (as suggested by choroba). And then use the possibly modified versions for comparision, not the original ones. HTH, Rata	[reply]
Re: Comparing Two Numbers by davido (Cardinal) on Jan 05, 2021 at 16:32 UTC
Version::Compare gets it right (right for what you are expecting): `perl -MVersion::Compare -E 'say Version::Compare::version_compare("450 +.80.82","450.57")' 1` [download] It's about 50 lines of code including whitespace and has no non-core dependencies at runtime. I've found it to be able to handle versions such as PHP versions, WordPress versions, and Linux-typical versions. Dave	[reply] [d/l]
Re^2: Comparing Two Numbers by Anonymous Monk on Jan 05, 2021 at 19:56 UTC
Yep. Once again the wisdom shows itself: "Check CPAN first!" No matter what it is you want to do, someone's probably already done it for you.	[reply]


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