小时代5-perl 常量、多维数组及变量的初始化

下面我们通过两段代码来了解一下perl中常量，数组，及变量的定义和初始化：

常量及数组的初始化：

#!/usr/bin/perl
use strict;
use warnings;
my $test = "asdf";
print "${test}_test2n";
#constant
use constant {
AAA => "aaa",
BBB=> "bbb",
MIN_TOTAL => 12,
SCORE_PASS => 90,
SCORE_RED => 70,
};
print AAA;
print SCORE_PASS;
#two dimesion arrays
my @steps = (
["aaa", "aaavalue"],
["bbb","bbbvalue"],
["ccc","cccvalue"]
);
print "n";
foreach my $i (0 .. $#steps){
print "$steps[$i][0]:$steps[$i][1]n";
}

变量的定义及初始化：

my $a1;
print "$a1n";
my $a2 = undef;
print "$a2n";
if(!defined($a1)){print "a1 is not definedn";}
if(!$a2){print "a2 is not definedn";}
my $a3='';
if(!$a3){print "a3 is empty stringn";}

在定义变量时一定要初始化，或者在使用时判断是否defined，很多的时候还需要判断是否为空字符串。 特别是在使用getopt::long或cgi->query获得参数后要检测是否定义，如果么有定义考虑给予默认值。

www.iefjh.com/gbdfxc
www.iefjh.com/gbdfyldl
www.iefjh.com/gbdfkhbl
www.iefjh.com/gbdfylkh
www.iefjh.com/gbylgbdf
www.iefjh.com/gggbdfylc
www.iefjh.com/gbdfsjzmdl
www.iefjh.com/gbdfylfl
www.iefjh.com/gbdfzmnyq
www.iefjh.com/gbdfyj
www.iefjh.com/gbdfxmf
www.iefjh.com/szdmdgbdf
www.iefjh.com/mdgbdf
www.iefjh.com/gbdfdhkh
www.iefjh.com/gbdfdlkh
www.iefjh.com/gbdfwtkh
www.iefjh.com/gbdfkh1581260
www.iefjh.com/gbdfylhbwz
www.iefjh.com/gbdfyq
www.iefjh.com/sygbdfyl
www.iefjh.com/gbdfylzmyq
www.iefjh.com/gbdfylyflm
www.iefjh.com/gbdfylcznl
www.iefjh.com/gbdfwz
www.iefjh.com/gbdftz
www.iefjh.com/gbdfdh
www.iefjh.com/gbdfsj
www.iefjh.com/gggbdf
www.iefjh.com/gbdfgfw
www.iefjh.com/gbdfkhw
www.iefjh.com/gbdfsh
www.iefjh.com/gbdfsjxz
www.iefjh.com/gbdfylsjxz
www.iefjh.com/gbdfwfm
www.iefjh.com/gbdfdtkh
www.iefjh.com/gbdfhy
www.iefjh.com/gbdfrhkh
www.iefjh.com/gbdfzdl
www.iefjh.com/gbdfw
www.iefjh.com/gbdfdtkmdl
www.iefjh.com/gbdfglw
www.iefjh.com/gbdfxjw
www.iefjh.com/gbdfwtkhzx
www.iefjh.com/gbdfwtdhkh
www.iefjh.com/gbdfwkh
www.iefjh.com/gbdfwthykh
www.iefjh.com/gbdftgy
www.iefjh.com/gbdfzmzc
www.iefjh.com/gbdfbjl
www.iefjh.com/gbdfylyq
www.iefjh.com/mdgbdfrqrh
www.iefjh.com/gbdfmdyjm
www.iefjh.com/mdgbdfaqm
www.iefjh.com/gbdfkmdl
www.iefjh.com/gbdfxwz
www.iefjh.com/gbdfwtzx
www.iefjh.com/gbdfdms
www.iefjh.com/gbdfzc
www.iefjh.com/gbdfsy
www.iefjh.com/gbdfwzx
www.iefjh.com/gbdfnyqb
www.iefjh.com/gbdfzj
www.iefjh.com/gbdfdz
www.ajieq.com/gbdf
www.ajieq.com/gbdfkh
www.ajieq.com/gbdfylw
www.ajieq.com/gbdfyl
www.ajieq.com/gbdfhykh
www.ajieq.com/1659988_comgbdf
www.ajieq.com/gbdfdhtz
www.ajieq.com/gbdfylpt
www.ajieq.com/gbdfshy
www.ajieq.com/gbdfzxkh
www.ajieq.com/gbdfgw
www.ajieq.com/gbdfwt
www.ajieq.com/gbdfylc
www.ajieq.com/gbdfdl
www.ajieq.com/gbdfxc
www.ajieq.com/gbdfyldl
www.ajieq.com/gbdfkhbl
www.ajieq.com/gbdfylkh
www.ajieq.com/gbylgbdf
www.ajieq.com/gggbdfylc
www.ajieq.com/gbdfsjzmdl
www.ajieq.com/gbdfylfl
www.ajieq.com/gbdfzmnyq
www.ajieq.com/gbdfyj
www.ajieq.com/gbdfxmf
www.ajieq.com/szdmdgbdf
www.ajieq.com/mdgbdf
www.ajieq.com/gbdfdhkh
www.ajieq.com/gbdfdlkh
www.ajieq.com/gbdfwtkh
www.ajieq.com/gbdfkh1581260
www.ajieq.com/gbdfylhbwz
www.ajieq.com/gbdfyq
www.ajieq.com/sygbdfyl
www.ajieq.com/gbdfylzmyq
www.ajieq.com/gbdfylyflm
www.ajieq.com/gbdfylcznl
www.ajieq.com/gbdfwz
www.ajieq.com/gbdftz
www.ajieq.com/gbdfdh
www.ajieq.com/gbdfsj
www.ajieq.com/gggbdf
www.ajieq.com/gbdfgfw
www.ajieq.com/gbdfkhw
www.ajieq.com/gbdfsh
www.ajieq.com/gbdfylsjxz
www.ajieq.com/gbdfwfm
www.ajieq.com/gbdfdtkh
www.ajieq.com/gbdfhy
www.ajieq.com/gbdfrhkh
www.ajieq.com/gbdfzdl
www.ajieq.com/gbdfw
www.ajieq.com/gbdfdtkmdl
www.ajieq.com/gbdfglw
www.ajieq.com/gbdfxjw
www.ajieq.com/gbdfwtkhzx
www.ajieq.com/gbdfwtdhkh
www.ajieq.com/gbdfwkh
www.ajieq.com/gbdfwthykh
www.ajieq.com/gbdftgy
www.ajieq.com/gbdfylwz
www.ajieq.com/gbdfzmzc
www.ajieq.com/gbdfbjl
www.ajieq.com/gbdfylyq
www.ajieq.com/mdgbdfrqrh
www.ajieq.com/gbdfmdyjm
www.ajieq.com/mdgbdfaqm
www.ajieq.com/gbdfkmdl
www.ajieq.com/gbdfxwz
www.ajieq.com/gbdfwtzx
www.ajieq.com/gbdfdms
www.ajieq.com/gbdfzc
www.ajieq.com/gbdfsy
www.ajieq.com/gbdfwzx
www.ajieq.com/gbdfnyqb
www.ajieq.com/gbdfzj
www.ajieq.com/gbdfdz
www.ndnbg.com/gbdf
www.ndnbg.com/gbdfkh
www.ndnbg.com/gbdfylw
www.ndnbg.com/gbdfyl
www.ndnbg.com/gbdfhykh
www.ndnbg.com/1659988_comgbdf
www.ndnbg.com/gbdfdhtz
www.ndnbg.com/gbdfylpt
www.ndnbg.com/gbdfshy
www.ndnbg.com/gbdfzxkh
www.ndnbg.com/gbdfgw
www.ndnbg.com/gbdfwt
www.ndnbg.com/gbdfylc
www.ndnbg.com/gbdfdl
www.ndnbg.com/gbdfxc
www.ndnbg.com/gbdfyldl
www.ndnbg.com/gbdfkhbl
www.ndnbg.com/gbdfylkh
www.ndnbg.com/gbylgbdf
www.ndnbg.com/gggbdfylc
www.ndnbg.com/gbdfsjzmdl
www.ndnbg.com/gbdfylfl
www.ndnbg.com/gbdfzmnyq
www.ndnbg.com/gbdfyj
www.ndnbg.com/gbdfxmf
www.ndnbg.com/szdmdgbdf
www.ndnbg.com/mdgbdf
www.ndnbg.com/gbdfdhkh
www.ndnbg.com/gbdfdlkh
www.ndnbg.com/gbdfwtkh
www.ndnbg.com/gbdfkh1581260
www.ndnbg.com/gbdfylhbwz
www.ndnbg.com/gbdfyq
www.ndnbg.com/sygbdfyl
www.ndnbg.com/gbdfylzmyq
www.ndnbg.com/gbdfylyflm
www.ndnbg.com/gbdfylcznl
www.ndnbg.com/gbdfwz
www.ndnbg.com/gbdftz
www.ndnbg.com/gbdfdh
www.ndnbg.com/gbdfsj
www.ndnbg.com/gggbdf
www.ndnbg.com/gbdfgfw
www.ndnbg.com/gbdfkhw
www.ndnbg.com/gbdfsh
www.ndnbg.com/gbdfsjxz
www.ndnbg.com/gbdfylsjxz
www.ndnbg.com/gbdfwfm
www.ndnbg.com/gbdfdtkh
www.ndnbg.com/gbdfhy
www.ndnbg.com/gbdfrhkh
www.ndnbg.com/gbdfzdl
www.ndnbg.com/gbdfw
www.ndnbg.com/gbdfdtkmdl
www.ndnbg.com/gbdfglw
www.ndnbg.com/gbdfxjw
www.ndnbg.com/gbdfwtkhzx
www.ndnbg.com/gbdfwtdhkh
www.ndnbg.com/gbdfwkh
www.ndnbg.com/gbdfwthykh
www.ndnbg.com/gbdftgy
www.ndnbg.com/gbdfylwz
www.ndnbg.com/gbdfbjl
www.ndnbg.com/mdgbdfrqrh
www.ndnbg.com/gbdfmdyjm
www.ndnbg.com/mdgbdfaqm
www.ndnbg.com/gbdfxwz
www.ndnbg.com/gbdfdms
www.ndnbg.com/gbdfzc
www.ndnbg.com/gbdfsy
www.ndnbg.com/gbdfwzx
www.ndnbg.com/gbdfnyqb
www.ndnbg.com/gbdfzj
www.ndnbg.com/gbdfdz
www.fpdpl.com/gbdf
www.fpdpl.com/gbdfkh
www.fpdpl.com/gbdfylw
www.fpdpl.com/gbdfyl
www.fpdpl.com/gbdfhykh
www.fpdpl.com/1659988_comgbdf
www.fpdpl.com/gbdfdhtz
www.fpdpl.com/gbdfylpt
www.fpdpl.com/gbdfshy
www.fpdpl.com/gbdfzxkh
www.fpdpl.com/gbdfgw
www.fpdpl.com/gbdfwt
www.fpdpl.com/gbdfylc
www.fpdpl.com/gbdfdl
www.fpdpl.com/gbdfxc
www.fpdpl.com/gbdfyldl
www.fpdpl.com/gbdfkhbl
www.fpdpl.com/gbdfylkh
www.fpdpl.com/gbylgbdf
www.fpdpl.com/gggbdfylc
www.fpdpl.com/gbdfsjzmdl
www.fpdpl.com/gbdfylfl
www.fpdpl.com/gbdfzmnyq
www.fpdpl.com/gbdfyj
www.fpdpl.com/gbdfxmf
www.fpdpl.com/szdmdgbdf
www.fpdpl.com/mdgbdf
www.fpdpl.com/gbdfdhkh
www.fpdpl.com/gbdfdlkh
www.fpdpl.com/gbdfwtkh
www.fpdpl.com/gbdfkh1581260
www.fpdpl.com/gbdfylhbwz
www.fpdpl.com/gbdfyq
www.fpdpl.com/sygbdfyl
www.fpdpl.com/gbdfylzmyq
www.fpdpl.com/gbdfylyflm
www.fpdpl.com/gbdfylcznl
www.fpdpl.com/gbdfwz
www.fpdpl.com/gbdftz
www.fpdpl.com/gbdfdh
www.fpdpl.com/gbdfsj
www.fpdpl.com/gggbdf
www.fpdpl.com/gbdfgfw
www.fpdpl.com/gbdfkhw
www.fpdpl.com/gbdfsh
www.fpdpl.com/gbdfsjxz
www.fpdpl.com/gbdfylsjxz
www.fpdpl.com/gbdfwfm
www.fpdpl.com/gbdfdtkh
www.fpdpl.com/gbdfhy
www.fpdpl.com/gbdfzdl
www.fpdpl.com/gbdfw
www.fpdpl.com/gbdfdtkmdl
www.fpdpl.com/gbdfglw
www.fpdpl.com/gbdfxjw
www.fpdpl.com/gbdfwtkhzx
www.fpdpl.com/gbdfwtdhkh
www.fpdpl.com/gbdfwkh
www.fpdpl.com/gbdfwthykh
www.fpdpl.com/gbdftgy
www.fpdpl.com/gbdfylwz
www.fpdpl.com/gbdfzmzc
www.fpdpl.com/gbdfbjl
www.fpdpl.com/gbdfylyq
www.fpdpl.com/mdgbdfrqrh
www.fpdpl.com/gbdfmdyjm
www.fpdpl.com/mdgbdfaqm
www.fpdpl.com/gbdfkmdl
www.fpdpl.com/gbdfxwz
www.fpdpl.com/gbdfwtzx
www.fpdpl.com/gbdfdms
www.fpdpl.com/gbdfzc
www.fpdpl.com/gbdfsy
www.fpdpl.com/gbdfwzx
www.fpdpl.com/gbdfnyqb
www.fpdpl.com/gbdfzj
www.fpdpl.com/gbdfdz
www.lrroc.com/gbdf
www.lrroc.com/gbdfkh
www.lrroc.com/gbdfylw
www.lrroc.com/gbdfyl
www.lrroc.com/gbdfhykh
www.lrroc.com/1659988_comgbdf
www.lrroc.com/gbdfdhtz
www.lrroc.com/gbdfylpt
www.lrroc.com/gbdfshy
www.lrroc.com/gbdfzxkh
www.lrroc.com/gbdfgw
www.lrroc.com/gbdfwt
www.lrroc.com/gbdfylc
www.lrroc.com/gbdfdl
www.lrroc.com/gbdfxc
www.lrroc.com/gbdfyldl
www.lrroc.com/gbdfkhbl
www.lrroc.com/gbdfylkh
www.lrroc.com/gbylgbdf
www.lrroc.com/gggbdfylc
www.lrroc.com/gbdfsjzmdl
www.lrroc.com/gbdfylfl
www.lrroc.com/gbdfzmnyq
www.lrroc.com/gbdfyj
www.lrroc.com/gbdfxmf
www.lrroc.com/szdmdgbdf
www.lrroc.com/mdgbdf
www.lrroc.com/gbdfdhkh
www.lrroc.com/gbdfdlkh
www.lrroc.com/gbdfwtkh
www.lrroc.com/gbdfkh1581260
www.lrroc.com/gbdfylhbwz
www.lrroc.com/gbdfyq
www.lrroc.com/sygbdfyl
www.lrroc.com/gbdfylzmyq
www.lrroc.com/gbdfylyflm
www.lrroc.com/gbdfylcznl
www.lrroc.com/gbdfwz
www.lrroc.com/gbdftz
www.lrroc.com/gbdfdh
www.lrroc.com/gbdfsj
www.lrroc.com/gggbdf
www.lrroc.com/gbdfgfw
www.lrroc.com/gbdfkhw
www.lrroc.com/gbdfsh
www.lrroc.com/gbdfsjxz
www.lrroc.com/gbdfylsjxz
www.lrroc.com/gbdfwfm
www.lrroc.com/gbdfdtkh
www.lrroc.com/gbdfhy
www.lrroc.com/gbdfrhkh
www.lrroc.com/gbdfzdl
www.lrroc.com/gbdfw
www.lrroc.com/gbdfdtkmdl
www.lrroc.com/gbdfglw
www.lrroc.com/gbdfxjw
www.lrroc.com/gbdfwtkhzx
www.lrroc.com/gbdfwtdhkh
www.lrroc.com/gbdfwkh
www.lrroc.com/gbdfwthykh
www.lrroc.com/gbdftgy
www.lrroc.com/gbdfylwz
www.lrroc.com/gbdfzmzc
www.lrroc.com/gbdfbjl
www.lrroc.com/gbdfylyq
www.lrroc.com/mdgbdfrqrh
www.lrroc.com/gbdfmdyjm
www.lrroc.com/mdgbdfaqm
www.lrroc.com/gbdfkmdl
www.lrroc.com/gbdfxwz
www.lrroc.com/gbdfwtzx
www.lrroc.com/gbdfdms
www.lrroc.com/gbdfzc
www.lrroc.com/gbdfsy
www.lrroc.com/gbdfwzx
www.lrroc.com/gbdfnyqb
www.lrroc.com/gbdfzj
www.lrroc.com/gbdfdz
www.yikgs.com/gbdf
www.yikgs.com/gbdfkh
www.yikgs.com/gbdfylw
www.yikgs.com/gbdfyl
www.yikgs.com/gbdfhykh
www.yikgs.com/1659988_comgbdf
www.yikgs.com/gbdfdhtz
www.yikgs.com/gbdfylpt
www.yikgs.com/gbdfshy
www.yikgs.com/gbdfzxkh
www.yikgs.com/gbdfgw
www.yikgs.com/gbdfwt
www.yikgs.com/gbdfylc
www.yikgs.com/gbdfdl
www.yikgs.com/gbdfxc
www.yikgs.com/gbdfyldl
www.yikgs.com/gbdfkhbl
www.yikgs.com/gbdfylkh
www.yikgs.com/gbylgbdf
www.yikgs.com/gggbdfylc
www.yikgs.com/gbdfsjzmdl
www.yikgs.com/gbdfylfl
www.yikgs.com/gbdfzmnyq
www.yikgs.com/gbdfyj
www.yikgs.com/gbdfxmf
www.yikgs.com/szdmdgbdf
www.yikgs.com/mdgbdf
www.yikgs.com/gbdfdhkh
www.yikgs.com/gbdfdlkh
www.yikgs.com/gbdfwtkh
www.yikgs.com/gbdfkh1581260
www.yikgs.com/gbdfylhbwz
www.yikgs.com/gbdfyq
www.yikgs.com/sygbdfyl
www.yikgs.com/gbdfylzmyq
www.yikgs.com/gbdfylyflm
www.yikgs.com/gbdfylcznl
www.yikgs.com/gbdfwz
www.yikgs.com/gbdftz
www.yikgs.com/gbdfdh
www.yikgs.com/gbdfsj
www.yikgs.com/gggbdf
www.yikgs.com/gbdfgfw
www.yikgs.com/gbdfkhw
www.yikgs.com/gbdfsh
www.yikgs.com/gbdfsjxz
www.yikgs.com/gbdfylsjxz
www.yikgs.com/gbdfwfm
www.yikgs.com/gbdfdtkh
www.yikgs.com/gbdfhy
www.yikgs.com/gbdfrhkh
www.yikgs.com/gbdfzdl
www.yikgs.com/gbdfw
www.yikgs.com/gbdfdtkmdl
www.yikgs.com/gbdfglw
www.yikgs.com/gbdfxjw
www.yikgs.com/gbdfwtkhzx
www.yikgs.com/gbdfwtdhkh
www.yikgs.com/gbdfwkh
www.yikgs.com/gbdfwthykh
www.yikgs.com/gbdftgy
www.yikgs.com/gbdfylwz
www.yikgs.com/gbdfzmzc
www.yikgs.com/gbdfbjl
www.yikgs.com/gbdfylyq
www.yikgs.com/mdgbdfrqrh
www.yikgs.com/gbdfmdyjm
www.yikgs.com/mdgbdfaqm
www.yikgs.com/gbdfkmdl
www.yikgs.com/gbdfxwz
www.yikgs.com/gbdfwtzx
www.yikgs.com/gbdfdms
www.yikgs.com/gbdfzc
www.yikgs.com/gbdfsy
www.yikgs.com/gbdfwzx