shiromuku(fs6)DIARY

Perl覚え書き

■Creating References

1. You can create areference to any named variable or subroutine with a backslash.
　　$scalarref = \$foo;
　　$arrayref = \@ARGV;
　　$hashref = \%ENV;
　　$coderef = \&handler;
　　$globref = \*STDOUT;

2. You can create areference to an anonymous array with square brackets.
　　$arrayref = [1,2,['a','b','c','d']];

3. You can create areference to an anonymous hash with braces.
　　$hashref = {'Adam' => 'Eve','Clyde' => $bonnie,'Antony' => 'Cleo' . 'patra',};

4. You can create areference to an anonymous subroutine by using sub without a subroutine name.
　　$coderef = sub{print "Boink!\n"}; #&$$coderef prints "Boink!"

5. References to filehandles or directory handles can be created by referring the typeglob of the same name.
　　&splutter(\*STDOUT);
　　Sub splutter {
　　　my $fh = shift;
　　　print $fh "..........\n";
　　}

6. References can be created by dereferencing them.

■Dereferencing References

1. Using a Variable as a Variable Name
　　$bar = $$scalarref;

　　push (@$arrayref, $filename);
　　$$arrayref[0] = "January";
　　@$arrayref[4..6] = qw/May June July/;

　　%$hashref = (KEY => "RING", BIRD => "SING");
　　$$hashref{KEY} = "VALUE";
　　@$hashref{"KEY1","KEY2"} = ("VAL1", "VAL2");

　　&$coderef(1,2,3);

2. Using a BLOCK as a Variable Name
　　$bar = ${$scalarref};

　　push (@{$arrayref}, $filename);
　　${$arrayref}[0] = "January";
　　@{$arrayref}[4..6] = qw/May June July/;

　　%{$hashref} = (KEY => "RING", BIRD => "SING");
　　${$hashref}{KEY} = "VALUE";
　　@{$hashref}{"KEY1","KEY2"} = ("VAL1", "VAL2");

　　&{$coderef}(1,2,3);

3. Using the Arrow Operator
　　$$arrayref[0] = "January";
　　${$arrayref}[0] = "January";
　　$arrayref->[0] = "January";
　　（上記のどの書き方でもOK）

　　&$coderef(1,2,3);
　　&{$coderef}(1,2,3);
　　$coderef->(1,2,3);
　　（上記のどの書き方でもOK）

　　$listref->[2][2] = "hello";
　　$$listref[2][2] = "hello";
　　（上記のどの書き方でもOK）

■Array of Arrays
※以下はすべて同じ

for $i (1..10) {
　@array = somefunc ($i);
　$AoA[$i] = [@array];
}

for $i (1..10) {
　@array = somefunc ($i);
　@{$AoA[$i]} = @array;
}

for $i (1..10) {
　my @array = somefunc ($i);
　$AoA[$i] = \@array;
}

for $i (1..10) {
　$AoA[$i] = [somefunc ($i)];
}

■Hash of Arrays

for $group ("simpsons", "jetsons","flintstones") {
　$HoA{$group} = [get_famly($group)];
}

$HoA{$group}[1] =~ s/(\w)/\u$1/; #最初の文字を大文字に

for $family (sort {@{$HaA{$b}} <=> @{$HaA{$a}}} keys %HoA) {
　print "$family: ", join(",", sort @{$HaA{$family}}), "\n";
} #各Arrayの要素数で、Hashのキーを多い方からソートして、キーと要素（アスキー順にソートしたもの）を順にプリント

■Hash of Hashes

for $family (sort {keys %{$HaH{$b}} <=> keys %{$HaH{$a}}} keys %HoH) {
　print "$family: ";
　for $role (sort keys %{$HaH{$family}}) {
　　print "$role=$HaH{$family}{$role}";
　}
　print "\n";
} #各Hashの要素数(キーの数）で、Hashのキーを多い方からソートして、キーと要素（アスキー順にソートしたもの）を順にプリント

2003年10月30日（木） No.47

Comment(0)