Re^4: Using map function to print few elements of list returned by sort function

With your hint, I was able to do the following

perl -F':' -lane '
push @{$h{$F[1]}}, [$F[0],$_] }{
print $_->[1] for map { splice [sort {$b->[0] <=> $a->[0]} @{$h{$_}}],
+0,4 } keys %h' file
20470:ZM:Samfya:Africa
20149:ZM:Sesheke:Africa
18638:ZM:Siavonga:Africa
699385:ZW:Bulawayo:Africa
61739:ZW:Chinhoyi:Africa
47294:ZW:Chegutu:Africa
37423:ZW:Bindura:Africa
[download]

Thanks LanX, your guidance was much appreciated.

Comment on Re^4: Using map function to print few elements of list returned by sort function Download Code

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Re^5: Using map function to print few elements of list returned by sort function by LanX (Saint) on May 26, 2014 at 11:24 UTC
this can be simplified (and will work with older perl-versions) `perl -F':' -lane ' push @{$h{$F[1]}}, [$F[0],$_] }{ print $_->[1] for map { ( sort {$b->[0] <=> $a->[0]} @$_ )[0..3] } val +ues %h' file 20470:ZM:Samfya:Africa 20149:ZM:Sesheke:Africa 18638:ZM:Siavonga:Africa 699385:ZW:Bulawayo:Africa 61739:ZW:Chinhoyi:Africa 47294:ZW:Chegutu:Africa 37423:ZW:Bindura:Africa` [download] Please note that countries with less than 4 cities will have empty lines. But I'd rather prefer chaining only maps... Cheers Rolf ( addicted to the Perl Programming Language) update to avoid empty lines skip the -l option `perl -F':' -ane ' push @{$h{$F[1]}}, [$F[0],$_] }{ print $_->[1] for map { ( sort {$b->[0] <=> $a->[0]} @$_ )[0..3] } val +ues %h' file 20470:ZM:Samfya:Africa 20149:ZM:Sesheke:Africa 18638:ZM:Siavonga:Africa 699385:ZW:Bulawayo:Africa 61739:ZW:Chinhoyi:Africa 47294:ZW:Chegutu:Africa 37423:ZW:Bindura:Africa` [download] elaboration values instead of keys `(List)[slice]` instead of splice -l chomps and sets auto-newline in $\	[reply] [d/l] [select]
Re^6: Using map function to print few elements of list returned by sort function by jaypal (Beadle) on May 26, 2014 at 15:16 UTC
Thanks Rolf, using values instead of keys does make a lot sense. Thank you for sharing this. :)	[reply]

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elaboration