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ru.perl
- RU.PERL ----------------------------------------------------------------------
From : Dmitry Smolin 2:5020/949 27 Sep 2002 02:14:16
To : Sergey V. Leschenko
Subject : Хеш списков
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Once, 26 Sep 2002 16:18, Sergey V. Leschenko wrote to Yuri Mashkovtsev:
>>> push @{ $nets{$name_comp}}, $n;
YM>> Здесь lvalue context. Поэтому $nets{$name_comp} автоматически
YM>> (autovivify) становится ссылкой на анонимный массив.
SL> а где про это подробней почитать?
perldoc perlreftut:
=== Cut ===
There's one fine point I skipped. Suppose the program has just read the
first line in its input that happens to mention Greece. Control is at
line 4, "$country" is "'Greece'", and "$city" is "'Athens'". Since this
is the first city in Greece, "$table{$country}" is undefined---in fact
there isn't an "'Greece'" key in "%table" at all. What does line 4 do
here?
4 push @{$table{$country}}, $city;
This is Perl, so it does the exact right thing. It sees that you want to
push "Athens" onto an array that doesn't exist, so it helpfully makes a
new, empty, anonymous array for you, installs it in the table, and then
pushes "Athens" onto it. This is called `autovivification'.
=== Cut ===
SL> imho не совсем логичное поведение.
Это как посмотреть. По-моему - в полне в духе perl'а. Читай "логичное".
Take care.
--- skanking to the rhythm of the music by my side
* Origin: SupportYourLocalSkaBand even though they just may stink (2:5020/949)
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