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davido, brad_nov:

I saw davido's solution, and played around with it to add a limit to the number of open files in %handles using a least-recently used (LRU) cache. No real reason, but I thought I'd amuse myself while my son got ready for bed.

You could trim it down a bit, as much of the code just implements traces to show what's happening as it runs.

$ cat #!/usr/bin/perl # Updated PM 1013651 to have a limit on file handles use strict; use warnings; use autodie; use 5.10.0; my %handles; my $MAX_OPEN_FH=3; while( <DATA> ) { my( $key ) = m/^[^|]\|([^|]+)/; if( ! defined $key ) { warn "Line $. appears malformed. Skipping: $_"; next; } print {FH("$key.txt")} $_; } close $$_{FH} for values %handles; sub FH { # Return file handle for named file state $cnt=0; my $key= shift; # Return current handle if it exists if (exists $handles{$key}) { $handles{$key}{cnt}=++$cnt; print "$key: (cnt=$cnt) found\n"; return $handles{$key}{FH}; } # Doesn't exist, retire the "oldest" one if we're at the limit if (keys %handles >= $MAX_OPEN_FH) { my @tmp = sort { $$a{cnt} <=> $$b{cnt} } values %handles; say "$key: Too many open files, close one: ", join(", ",map { "$$_{FName}:$$_{cnt}" } @tmp); my $hr = $tmp[0]; print " closing $$hr{FName}\n"; close $$hr{FH}; delete $handles{$$hr{FName}}; } open my $FH, '>>', $key; $handles{$key} = { cnt=>++$cnt, FName=>$key, FH=>$FH }; print "$key: opened new file ($cnt)\n"; return $FH; } __DATA__ a|1|foo b|1|bar c|2|baz d|1|xyzzy e|2|blarg f|2|The g|3|quick h|2|red i|2|fox j|3|jumped k|4|over l|1|the m|1|lazy n|1|brown o|1|dog p|5|gorgonzola

Running it gives me:

$ ./ 1.txt: opened new file (1) 1.txt: (cnt=2) found 2.txt: opened new file (3) 1.txt: (cnt=4) found 2.txt: (cnt=5) found 2.txt: (cnt=6) found 3.txt: opened new file (7) 2.txt: (cnt=8) found 2.txt: (cnt=9) found 3.txt: (cnt=10) found 4.txt: Too many open files, close one: 1.txt:4, 2.txt:9, 3.txt:10 closing 1.txt 4.txt: opened new file (11) 1.txt: Too many open files, close one: 2.txt:9, 3.txt:10, 4.txt:11 closing 2.txt 1.txt: opened new file (12) 1.txt: (cnt=13) found 1.txt: (cnt=14) found 1.txt: (cnt=15) found 5.txt: Too many open files, close one: 3.txt:10, 4.txt:11, 1.txt:15 closing 3.txt 5.txt: opened new file (16)


When your only tool is a hammer, all problems look like your thumb.

In reply to Re^2: Split a file based on column by roboticus
in thread Split a file based on column by brad_nov

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