我试图找出如何在if / else块中使用相同的变量.例如,
$var1 $var2 $var3 if(condition) { ... } else { ... }
我需要在块中访问$vars1,2和3,但我不能.我想我有一个范围问题.我尝试将它们设为全局,但我看到很多错误并且程序运行不正常.我错过了什么?
这是我的代码.我的问题是服务器需要底部的变量(@varList等),因为这是一个也使用CGI的apache服务器上的脚本.它吐出这样的错误:
[error] Global symbol "$questionslist" requires explicit package name at /home/megaoff/www/vi ewquestions.dhtml line 46.\nGlobal symbol "$site" requires explicit package name at /home/megaoff/www/viewquestions.dhtm l line 46.\nGlobal symbol "$xs" requires explicit package name at /home/megaoff/www/viewquestions.dhtml line 46.\nGlobal symbol "$username" requires explicit package name at /home/megaoff/www/viewquestions.dhtml line 46.\n #!/usr/bin/perl use strict; use CGI; use BarryP; my $pagev = BarryP::makeP("noextracook",1); my $bvga = $pagev->{'vga'}; my %vga = %$bvga; my $cgi = CGI->new; my $usePage = "answerquestions.html"; my $anslist = "/home/megaoff/www/limages/anslist.txt"; my $unanslist = "/home/megaoff/www/limages/unanslist.txt"; my $action = $vga{"action"}; if($action eq 'adminmode') { my @a_list = $pagev->listFile($anslist); my %list = map { split(/\t/,$_,2) } @a_list; } else { my @u_list = $pagev->listFile($unanslist); chomp @u_list; my %questions = map { $_ => '' } @u_list; my $question = $cgi->param('question'); my $answer = $cgi->param('answer'); chomp($question,$answer); open(my $ANS,'>>',$anslist) or die "Can't open file $anslist: $!"; print $ANS "$question\t$answer\n"; close($ANS) or die "Can't close file $anslist: $!"; delete $questions{$question}; open(my $UNANS,'>',$unanslist) or die "Can't open file $unanslist: $!"; print $UNANS "$_\n" foreach keys %questions; close($UNANS) or die "Can't close file $unanslist: $!"; my $questionslist = join("<br>",@u_list); my $site = $pagev->{'site'}; my $xs = $pagev->{'xs'}; my $username = $pagev->{'username'}; } my @varList = ('questionslist',$questionslist,'action',$action,'site',$site,'xs',$xs,'$username',$username); $pagev->pageHeader($usePage,@varList);
解决方法
你的问题在于范围界定.在第46行,当您引用$questionlist等时,它们已经超出了范围,因为您在else块中定义了它们.
你有(简化):
if ($blah) { # do stuff } else { # do other stuff my $variable = "something"; } doSomethingWith($variable); # illegal,$variable is not in scope.
$variable不在else块之外定义,else块甚至可能不会被执行.您需要将函数放在else块中,或者找到一些方法来赋予这些变量默认值,并在if语句之前声明它们.