"42" ~~ "42.0" is false in 5.10

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

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Re: "42" ~~ "42.0" is false in 5.10 by syphilis (Archbishop) on Dec 24, 2007 at 13:17 UTC
IMHO they should be compared as numbers but they are compared as strings Well ... they are both strings ... and you are doing nothing that dictates that those strings should be numified. The behaviour seems totally reasonable to me. OTOH, `"42" * 1 ~~ "42.0" * 1` should (and does) evaluate as true - because, in this instance, something is being done to numify the strings. Cheers, Rob	[reply] [d/l]
Re^2: "42" ~~ "42.0" is false in 5.10 by tomfahle (Priest) on Jan 24, 2008 at 17:09 UTC
Hi, To me it looks right: If it looks like a string, it will be treated as string. Here's a small programm to test the new ~~ Operator. use strict; use warnings; use 5.010; ## No quotes &test_smartmatch(42, 42); # yields 42 smartmatches 42 &test_smartmatch(42,42.0); # yields 42 smartmatches 42 ## Single Quotes &test_smartmatch(42,'42.0'); # yields 42 smartmatches 42.0 &test_smartmatch('42','42.0'); # yields 42 doesn't smartmatch 42.0 ## Double Quotes &test_smartmatch("42","42.0"); # yields 42 doesn't smartmatch 42.0 ########################################################### sub test_smartmatch { my $lhs = shift @_; # Left Hand Side (LHS) my $rhs = shift @_; # Right Hand Side (RHS) if ( $lhs ~~ $rhs ) { say "$lhs smartmatches $rhs"; } else { say "$lhs doesn't smartmatch $rhs"; } } ## ########################################################### __END__ [download] Just my 2 cents. Hope this helps.	[reply] [d/l]
Re: "42" ~~ "42.0" is false in 5.10 by FunkyMonk (Bishop) on Dec 24, 2007 at 13:09 UTC
From perlsyn `the first row that applies, in either order, determines the match beha +viour ... Num numish[!] numeric equality $a == $b Any Str string equality $a eq $b Any Num numeric equality $a == $b Any Any string equality $a eq $b` [download] So surely it's using the second case (Any ~~ Str) using string equality.	[reply] [d/l] [select]
Re^2: "42" ~~ "42.0" is false in 5.10 by szabgab (Priest) on Dec 24, 2007 at 13:13 UTC
yes, I see that it is correct based on the perlsyn. The question what is the clever reasoning behind the fact that there is no numish ~~ numish using == rule in the table slightly above the Any ~~ Str?	[reply]
Re^2: "42" ~~ "42.0" is false in 5.10 by jettero (Monsignor) on Dec 24, 2007 at 13:12 UTC
Indeed. So then `42 ~~ "42.0"` would probably be true. I need to get 5.10 installed. I wonder how long before the ubuntu devs will have it ready. -Paul	[reply] [d/l]
Re: "42" ~~ "42.0" is false in 5.10 by TOD (Friar) on Dec 24, 2007 at 13:07 UTC
i don't know anything about perl 5.10 yet. however, a string is a string, and from a string's point of view 42 is rather not 42.0 - retrieve a 0.0 value through DBI and ask whether it's true or not. ;) -------------------------------- masses are the opiate for religion.	[reply]
Re: "42" ~~ "42.0" is false in 5.10 by ysth (Canon) on Dec 24, 2007 at 21:23 UTC
This corresponds closely to how the bitwise operators work: if either operand is a number or has been used in a numeric context, it's a numeric operation, otherwise it's a string operation. I like it, and would be unhappy to see it work any differently. May I suggest you use the +0~~ (aka ~~0+) operator? -- CollegeGear.com - more than just college gear (though, yes, we have college-branded teddy bears)	[reply]
Re^2: "42" ~~ "42.0" is false in 5.10 by FunkyMonk (Bishop) on Dec 25, 2007 at 02:00 UTC
The +sperm and sperm+ operators? :-)	[reply] [d/l] [select]