作者:
Neisseria (Neisseria)
2014-11-27 16:04:31※ 引述《b13b46o2 (買槍買裝備)》之銘言：
: $ANS=1234 ;
: $count = $ANS =~ tr/1234// ;
: print "$count\n";
: 請問tr後面有辦法帶入自己想要的變數嗎？
: google了好久
: $ANS=1234 ;
: print "Please enter your number.\n";
: chomp ($num=<STDIN>);
: $count = $ANS =~ tr/// ;
: print "$count\n";
: tr後面該怎麼改才有辦法讓＄num帶入
簡單地說，請用 eval
其實 Perl 官方文件就有說明了
Because the transliteration table is built at compile time,
neither the SEARCHLIST nor the REPLACEMENTLIST are subjected to
double quote interpolation. That means that if you want to use
variables, you must use an eval():
eval "tr/$oldlist/$newlist/";
die $@ if $@;