Re: How to make this substitutions without splitting the strings?

AnomalousMonk pretty much nailed it. The string-based approach appears about 8 times faster than unpack/pack.

#! /usr/bin/perl

sub m_upk {
    (my $p = shift) =~ tr/-\0-\377/xc/;
    pack 'c*', unpack $p, shift;
}

sub m_and {
    (my $p = shift) =~ tr/-\0-\377/\0\377/;
    ($p &= shift) =~ tr/\0//d;
    $p;
}

chomp (our ($str1, $str2) = <DATA>);

use Benchmark 'cmpthese';
cmpthese -5, {
    unpack => q( m_upk $str1, $str2 ),
    string => q( m_and $str1, $str2 ),
};

__DATA__
---DAAAGLRG--G--G-P-LT-I--A--PG----A-----T----LG---G-YG---------------
+-------------------------SVT-----------------------------------------
+--------------------------------------------G-------NV-T------NN---G-
+---TI----SVANALPSLASSLPGDFRIF----------------------------------------
+-------------------GTLTNAGVVELRGRVVGN--G-LA-V-S------------G--------N
+---Y---VGQN----------------------GAVN-------------MN-TT---------L--AG
+--D------------------------------------------------------------------
+---------------------------------------------------------------------
+---------------------------------------------------------------------
+---------------------------------------------G---------------------A-
+------PS-------D-TL-LI---------------GGVPA-VATAS---------G----K------
+--T----T---------L---------------------------------------------------
+-------N-----VTNVGG---------------AGAL-------------------------------
+-----------------------------------TK-SDGI---------RL-VY-------------
+---AVNFA-N---------T-------------------G---N-A--F--TLAG----GTVS--AG--
+---------------------------------------------------------------------
+--AYSYY--------------LV--KGGV-T--------------------------------------
+---------------------------------------------------------------------
+---------------------------------------------------------------------
+---------------------------------------------------------------------
+---------------------------------------------------------------------
+---------------------------------------------------------------------
+-------------A-----------------LTG---------EDWYLR-S------------------
+--------------------------------------------TVPPR-P-DQ---P-----------
+---------------------------------------------------------------------
+---------------------------------------------------------------------
+---------------------------------------------------------------------
+---------------------------------------------------------------------
+---------------------------------------------------------------------
+---------------------------------------------------------------------
+---------------------------------------------------------------T-QQ--
+PPF------------------------------------------------------------------
+--------------S--V-A---DG-TP-ES--I-----------V------------------E--AV
+-K---N----------------A--AP-DA---------------------------------------
+-------------------------------------------------K-------PEP---------
+-----------------------------------------------------V---------------
+---YR----------------------------------------------------------------
+---PEV--PL-YS-----------EVP------------------------------------------
+---------------------------------------------------------------------
+--------------------------------------A--VARQ----------------------LG
+---L-L------------Q--------IDT-F-H----------------DRQ-------G-EQG--LL
+-----AEN-G-S---------------------------------------------------------
+---------------------------------------------------------------------
+--------------------------------------------------------------------V
+P----VSWSRVW-----------GGY---SN------IKQ-NG--------------------------
+DVTPSY--DGTVW-----G--MQVGQ---DLY-----ADNRP-------SGHRNHYGFF----LGF---
+---SR--AIGDVNGFA--------------------------------------LAQPDL--------G
+VGSLQVN-A-Y-N----L--G--G-YWT-----------------------------H----IGPG---
+-----------GWYTDA--------------------------VV--MGS-V--LT---V--RTHSN--
+-----------------------------N------NVSGS--T-D--GNA--VTGS-V--EAGV--P-
+-I------------SL------G-YG----------L--------------T----L---------E-P
+QA-QLLW-QWLS-LA--RFND------G-------V---------------------------------
+-SDV----T--W-----NN-GNTFLGR----IG-ARL--------QY-----AFDAN------GVSWK-
+-------------------PYLRVNVLR--S--FG-S--DD----------RTT-----FG-----GS-
+---TT------------------------IG-TQ-VG-------Q--T--AGQIGA-GL-VA-Q--LT-
+KR----GSVYA--T--V--S---Y---------LT-NL-----GG----E----H----QR----T---
+I--T---GNAGVRW--
XXXXXXXXXXX..X..X.X.XX.X..X..XX....X.....X....XX...X.XX...............
+.........................XXX.........................................
+............................................X.......XX.X......XX...X.
+...XX....XXXXX.......................................................
+..................................XXX..X.XX.X.X............X........X
+...X...XXXX......................XXXX.............XX.XX.........X..XX
+..X..................................................................
+.....................................................................
+.....................................................................
+.............................................X.....................X.
+......XX.......X.XX.XX...............XXX......XX.........X....X......
+..X....X.........X...................................................
+.......X.....XXXXXX................XXX...............................
+...................................XX.XXXX.........XX.X..............
+....XXXX.X..X....X.X...................X...X.X..X..XXX......XXX..XX..
+.....................................................................
+..XXXXX..............XX..XXXX.X......................................
+.....................................................................
+.....................................................................
+.....................................................................
+.....................................................................
+.....................................................................
+.............X..............XXXXXX.........XXXXXX.X..................
+............................................XXXXX.X.XX...X...........
+.....................................................................
+.....................................................................
+.....................................................................
+.....................................................................
+.....................................................................
+.....................................................................
+...............................................................X.XX..
+XXX.........XX..X...X................................................
+..............X..X.X...XX.XX.XX..X...........X..................X..XX
+.X...X................X..XX.XX.......................................
+.................................................X.......XXX.........
+.....................................................X...........X..X
+.X.XX................................................................
+...XXX..XX.XX...........XXX..........................................
+.....................................................................
+......................................X..XXXX......................XX
+...X.XX.........XXX........XXX.X.X................XXX.......X.XXX..XX
+......XX.X.X.........................................................
+.....................................................................
+....................................................................X
+X....XIIIIII...........III...II.......XXXX...........................
+.XXXXX..XXXXX.....X..XXXXX...XXX.....XXX............XXXXXXX....XXX...
+...XX..XXXXXX.............................................X..........
+.XXXXXX.X.X.X....X..X..X.XXX.............................X....XXXX...
+............XXXXX..........................XX..XXX.X..XX...X..XXXXXX.
+XX..XX......................XX......XXXXX..X.X..XXX..XXXX.X..XXXX..X.
+.X............XX......X..X..........X..............X....X.........X.X
+XX.XXXX.XXXX.XX..XXXX......X.......XX....X....................X.X....
+.XXX....X..X.....XX.XXXXXXX....XX.XXX........XX.....XXXXX......XXXXX.
+...................XXXXXXXXX..X..XX.X..XX....XX...XXXX.....XX.....XX.
+...XX............X....XX....XXX.XX.XX.......X..X..XXXXXX.XX.XX.X..XX.
+XX....XXXXX..X..X..X...X.........X...X......X....X....X....XX....X...
+X..X...XXXXXXXXX
[download]

          Rate unpack string
unpack  8128/s     --   -87%
string 61949/s   662%     --

Comment on Re: How to make this substitutions without splitting the strings? Download Code

Replies are listed 'Best First'.
Re^2: How to make this substitutions without splitting the strings? (tr/// behavior) by AnomalousMonk (Archbishop) on Aug 01, 2014 at 04:49 UTC
`(my $p = shift) =~ tr/-\0-\377/\0\377/;` In the `tr/-\0-\377/\0\377/` expression, the `'-'` (hyphen) character appears twice in the search list: initially, and also within the `\0-\377` range. In tests I did with some Win32 Perls in the range 5.8 to 5.14, the test code `c:\@Work\Perl\monks>perl -wMstrict -le "my $s = 'XXXooX'; (my $t = $s) =~ tr/XoX/ab/; print qq{'$t'}; " 'aaabba'` [download] (and identically for `tr/X\x00-\xff/ab/`) always produced the same result: the leftmost occurrence of a character in the search list is selected for matching to and replacement by the corresponding character in the replacement list. I considered using the much neater `tr/-\0-\377/\0\377/` version, but I couldn't find anything in the docs to guarantee the behavior shown in my tests must always prevail. Despite the tests, I didn't feel comfortable using an "undocumented feature". Do you know of any documentation of this "leftmost match" feature in the `tr///` built-in? In a regex, the rule would be "leftmost longest match", but `tr///` isn't really a regex, it's a transliterator — isn't it?	[reply] [d/l] [select]
Re^3: How to make this substitutions without splitting the strings? (tr/// behavior) by farang (Chaplain) on Aug 01, 2014 at 05:22 UTC
Do you know of any documentation of this "leftmost match" feature in the tr/// built-in? From perlop: "If multiple transliterations are given for a character, only the first one is used: `tr/AAA/XYZ/` will transliterate any A to X."	[reply] [d/l]
Re^4: How to make this substitutions without splitting the strings? (tr/// behavior) by AnomalousMonk (Archbishop) on Aug 01, 2014 at 05:34 UTC
Ah, the undocumented, documented! That feels better! I looked for just this sort of assertion (a couple of times) and couldn't find it. Thanks!	[reply]