Re^2: Syntax Perl Version support $c = () = $a =~ /\./g

in reply to Re: Syntax Perl Version support $c = () = $a =~ /\./g
in thread Syntax Perl Version support $c = () = $a =~ /\./g

jwkrahn, I had to test this, and lo, as you said, tr/.// is about 80% or so faster. I mean, of course, I'd have to run it thousands of times, but there it is, much faster. Thanks for that tip. I'm not clear on what you meant by this:

But note that while the first version will work with strings of any length the second version will only work with characters.

The data is a string of varying lengths, and usually is a decimal number.

Comment on Re^2: Syntax Perl Version support $c = () = $a =~ /\./g

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Re^3: Syntax Perl Version support $c = () = $a =~ /\./g by mr_mischief (Monsignor) on Jul 17, 2018 at 23:12 UTC
`tr///` (sometimes spelled `y///`, especially in code golf) works on characters specifically. `m//` (sometimes spelled `//`) works on regular expression matches, which may concern one or more characters (or in special cases zero, such as `split //, $foo;`). Perl takes text very seriously. There is a load to know about processing text in Perl, but the basics are pretty quick to grasp. The full story is not complete without at least these manual pages, although for this specific topic the first few should suffice.: m// s/// tr/// split index substr length lc uc lcfirst ucfirst reverse chr ord pack unpack perlop (especially eq ne gt lt ge le cmp . x =~ .. ) perlrequick perlretut perlreref perlre perlfaq6 perlrebackslash perlrecharclass perluniintro perlunitut perlunifaq perlunicode perluniprops perlvar (especially $_ $1 $a $b $\| $" $` $& $' $, $. $/ and $\ but especially especially $_ and $1 perllocale You might hope you never need to read perlebcdic, but there's that too.	[reply] [d/l] [select]
Re^4: Syntax Perl Version support $c = () = $a =~ /\./g by morgon (Priest) on Jul 18, 2018 at 00:09 UTC
tr/// (sometimes spelled y/// Hm, I have been using perl for something like 20 years and even though I have never (as far as I can remember) used tr at all I always knew it existed and what it does. "tr" must be short for "translate", but today I learn there is even another version of it - you can trade "tr" for "y" - well who would have guessed. As I am (a bit) interested in perl-arcana: Does anyone know where this "y" comes from? Is is a reference to another language who's users larry wanted to feel at home? Can anyone please enlighten me? Many thanks!	[reply]
Re^5: Syntax Perl Version support $c = () = $a =~ /\./g by choroba (Cardinal) on Jul 18, 2018 at 00:13 UTC
> Is is a reference to another language who's users larry wanted to feel at home? Exactly. y/// comes from sed. ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7**2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l]

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