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in reply to Re^6: list of four digit lock combinations without repeated digits
in thread list of four digit lock combinations without repeated digits

 push @x, pack "A*", qq[@$_] while $_=$i->next;

That would probably match if not beat join, if you weren't stringifying the array twice.

Ie. Use  push @x, pack "(A*)*", @$_ while $_=$i->next;

Of course, if you want to put all the sequences as strings into an array, this is easier and probably quicker;

my @x = map join( '', @$_ ), variations_with_repetition( ["a".."z"], 4
+ );;

print scalar @x;;
456976

[download]

And if all you want to do is print the count, then:

[ 7:10:21.87] C:\test>perl -MAlgorithm::Combinatorics=:all -le"print s
+calar( () = variations_with_repetition( ["a".."z"], $ARGV[0] ) )" 4
456976

[ 7:10:27.12] C:\test>

[download]

BTW, that is one seriously quick machine you're running. What is it? (6x faster than my (admittedly ancient) box.

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Re^8: list of four digit lock combinations without repeated digits
by usemodperl (Beadle) on Jun 22, 2018 at 23:57 UTC
    That would probably match if not beat join, if you weren't stringifying the array twice.

    Actually you did that previously and I carelessly cargo-culted it into my code.
    However upon testing it's actually very slightly faster! I don't know why:
    perl -MBenchmark=:all -MAlgorithm::Combinatorics=:all -wle'
for ("1".."4") {
my $t0 = Benchmark->new;
my $i  = variations_with_repetition(["a".."z"],$ARGV[0]); 
my @x; push @x, pack "(A*)*", @$_ while $_=$i->next;
my $t1 = Benchmark->new;
my $ts = timestr(timediff($t1,$t0));
print $ts }' 4

    [download]
    1 wallclock secs ( 0.77 usr +  0.01 sys =  0.78 CPU)
1 wallclock secs ( 0.77 usr +  0.01 sys =  0.78 CPU)
1 wallclock secs ( 0.75 usr +  0.00 sys =  0.75 CPU)
1 wallclock secs ( 0.75 usr +  0.01 sys =  0.76 CPU)



    perl -MBenchmark=:all -MAlgorithm::Combinatorics=:all -wle'
for ("1".."4") {
my $t0 = Benchmark->new;
my $i  = variations_with_repetition(["a".."z"],$ARGV[0]); 
my @x; push @x, pack "A*", qq[@$_] while $_=$i->next;
my $t1 = Benchmark->new;
my $ts = timestr(timediff($t1,$t0));
print $ts }' 4

    [download]
    0 wallclock secs ( 0.74 usr +  0.01 sys =  0.75 CPU)
1 wallclock secs ( 0.72 usr +  0.01 sys =  0.73 CPU)
1 wallclock secs ( 0.73 usr +  0.00 sys =  0.73 CPU)
1 wallclock secs ( 0.74 usr +  0.01 sys =  0.75 CPU)



    perl -MBenchmark=:all -MAlgorithm::Combinatorics=:all -wle'
for ("1".."4") {
my $t0 = Benchmark->new;
my $i  = variations_with_repetition(["a".."z"],$ARGV[0]); 
my @x; push @x, join "", @$_ while $_=$i->next;
my $t1 = Benchmark->new;
my $ts = timestr(timediff($t1,$t0));
print $ts }' 4

    [download]
    1 wallclock secs ( 0.65 usr +  0.01 sys =  0.66 CPU)
1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU)
0 wallclock secs ( 0.63 usr +  0.00 sys =  0.63 CPU)
1 wallclock secs ( 0.64 usr +  0.01 sys =  0.65 CPU)
    BTW, that is one seriously quick machine you're running. What is it? 
    
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