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| -rw-r--r-- | challenge-166/james-smith/README.md | 78 |
1 files changed, 74 insertions, 4 deletions
diff --git a/challenge-166/james-smith/README.md b/challenge-166/james-smith/README.md index 81a7fcb76c..6c17d94b01 100644 --- a/challenge-166/james-smith/README.md +++ b/challenge-166/james-smith/README.md @@ -96,10 +96,78 @@ If we include the g->9 mapping we can have: ``` glossologists 0x 0000 91055 0109 1575 ( 2,551,232,066,033,013) ``` -# Challenge 2 - Z-diff +# Challenge 2 - k-diff ## The solution +I approached this in a few different ways: + +### Getting the filenames... + +We can: + 1) Cheat - and create a hash of arrays; + 2) Use `opendir`/`readdir`/`closedir`; + 3) Use `blob '*/*'`; + 4) Use `<*/*>`. + +Each have advantages/disadvantages: + + * the first doesn't require us to create files on disk for testing; + * 2 allows you to find hidden file names but then you have to be careful with `.` & `..`. You have to join directory and filename to get the path + * 3 & 4 are essentially the same and get all "folders/entries". You have to split the path to get the directory and filename. + +The simplest approach is to use 3/4. + +```perl + my %directories; + for my $path ( sort blob '*/*' ) { + my( $dir, $file ) = split m{/}, $path; + push @{ $directories{$dir} }, -d $path ? "$file/" : $file; + } +``` + +### Finding a complete list of different filenames + +```perl + my @paths = sort keys %directories; + my %filename_counts; + for my $path ( @paths ) { + $filename_counts{ $_ }++ for @{$directories{ $path }}; + } +``` + +### Build templates for printing page horizontal line, sprintf table of heading/contents + +```perl + my $HORIZONTAL_LINE = join '-' x ( $length+2 ), ('+') x (1+@paths); + my $TEMPLATE = '|' . " %-${length}s |" x @paths; + + say $HORIZONTAL_LINE; + say sprintf $TEMPLATE, @paths; + say $HORIZONTAL_LINE; +``` + +### Workout what to print: + +``perl + ## map({$u{$F=$_}<@p?sprintf$T,map{($d{$_}[0]//'')ne$F?'': + ## shift@{$d{$_}}}@p:map{shift@{$d{$_}};()}@p}sort keys%u) + for my $filename ( sort keys %filename_counts ) { + if( $filename_counts{ $filename } == @paths ) { + shift @{$_} for values %directories; + next; + } + my @columns; + for (@paths) { + if( @{$directories{$_}} && $directories{$_}[0] eq $filename ) { + push @columns, shift @{$directories{$_}}; + } else { + push @columns, ''; + } + } + say sprintf $TEMPLATE, @columns; + } +``` ## The full code (with comments) ```perl @@ -115,9 +183,9 @@ sub z_diff { ## For directories add a trailing slash... ## (@_=split/\//),push@{$d{$_[0]}},-d$_?"$_[1]/":$_[1]for sort<*/*>; - for( sort <*/*> ) { - my($dir,$file) = split m{/}; - push @{ $directories{$dir}}, -d $_ ? "$file/" : $file; + for my $pat ( sort blob '*/*' ) { + my( $dir, $file ) = split m{/}, $path; + push @{ $directories{$dir} }, -d $path ? "$file/" : $file; } ## Get out an ordered list of directories... @@ -227,3 +295,5 @@ for<*/*>;$u{$_}++for map{@{$d{$_}}}my@p=sort keys%d;$l<length?$l=length:1for@p, - When a "string" starts with a number than has a letter in it treats it as if to add a space between the number and the rest of the string so we can rewrite `1 for $condition` as `1for$condition`. + - we don't need to do `sort blob '*/*'` or `sort <*/*>` as for all "current" + versions of Perl we can assume that perl does this for us. |