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使用sprintf函数对变量n位补零。

【代码】perl——获取数组中元素的索引。

#perl 5.26.1 my %food = ( 'apple' => 'fruit', 'pear' => 'fruit', 'carrot' =>'vegetable');my @mykey = keys %food;print "@mykey\n";foreach my $key (keys %food){print "$key : $food{$key}\n";}运行结果：apple carrot pearapple : fruitcarrot

my @player=('reggie','batum','mann');foreach my $i(@player){ #这里的i相当于索引值print "$i\n"}运行结果：reggiebatummann

#perl 5.26.1 my $a="Hello World";my $b=substr($a,3,5);my $c=lc($a);print "$b\n";print "$c\n";my $team=join(' and ','reggie','batum','mann');print "$team";运行结果：lo Wohello worldreggie and batum and mann

#perl 5.26.1 #使用数组和hash的地址来传递数据，并在需要时根据地址恢复出实际值my %team=('first man' => 'kawhi leonard',"second man" => "paul george");$teamref=\%team;%newteam=%$teamref;print "$teamref\n";print "$newteam{'first man'}\n";运行结果：HASH(0x56418e877ae0)kawh

#perl 5.26.1 my %team=('first man' => 'kawhi leonard',"second man" => "paul george");print "$team{'first man'}\n";print $team{'second man'};可以看到，在创建hash数组的时候，使用单引号和双引号都是可以的，如果要打印数组中的值，在指定key的时候则需要使用单引号。在菜鸟教程的perl教程中也有对单双引号的说明，链接如下。Perl 基础