第9章数据结构

<pre name="code" class="sql">9.1 数组的数组:


有许多种类型的嵌套数据结构,最容易做的是制作一个数组的数组,也叫做两维数组或者矩阵。


9.1.1   创建和访问一个两维数组:


下面是如何把一个两维数组放在一起的方法:


##给一个数组赋予一个数组引用列表:


zjzc01:/root/big2# cat a17.pl 
@Aoa = (
["fred", "barney" ],
["george", "jane", "elroy" ],
["homer", "marge", "bart" ],
);


print $Aoa[0][1]."
";
zjzc01:/root/big2# perl a17.pl 
barney

整个列表都封装在圆括弧里,而不是花括弧里,因为你是给一个俩别哦复制而不是给引用赋值。


如果你想要一个指向数组的引用,那么你要使用方括弧:


##创建一个指向一个数组的数组的引用:

zjzc01:/root/big2# cat a18.pl 
$ref_to_AoA = [
[ "fred", "barney", "pebbles", "bamm bamm", "dino", ],
[ "homer", "bart", "marge", "maggie", ],
[ "george", "jane", "elroy", "judy", ],
];

print $ref_to_AoA->[0][fred]."
";
print $$ref_to_AoA[0][fred]."
";
zjzc01:/root/big2# perl a18.pl 
fred
fred

 请记住在每一对相邻的花括弧或方括弧之间有一个隐含的-> ，因此下面两行:

$AoA[2][3]
$ref_to_AoA->[2][3]

等效于下面两行：

$AoA[2]->[3]
$ref_to_AoA->[2][3]


9.2 数组的散列的组成:

你可以用下面的方法创建一个匿名数组的散列:

##如果键字是标示符,我们通常省略引号:

zjzc01:/root/big2# cat a20.pl 
%HoA = (
flintstones => [ "fred", "barney" ],
jetsons => [ "george", "jane", "elroy" ],
simpsons => [ "homer", "marge", "bart" ],
);

print %HoA;
print "
";
print $HoA{flintstones}[0]."
";
zjzc01:/root/big2# perl a20.pl 
simpsonsARRAY(0x1c29560)jetsonsARRAY(0x1c292c0)flintstonesARRAY(0x1c0cd48)
fred


9.3   散列的数组:

如果你有一堆记录,你想顺序访问它们,并且每条记录本身包含一个键字/数值对,那么散列的数组就很有用。


在本章中,散列的数组比其他结构用得少一系。

9.3.1  组成一个散列的数组:

你可以用下面的方法创建一个匿名散列的数组:

zjzc01:/root/big2# cat a21.pl 
@AoH = (
{
husband => "barney",
wife => "betty",
son => "bamm bamm",
},
{
husband => "george",
wife => "jane",
son => "elroy",
},
{
husband => "homer",
wife => "marge",
son => "bart",
},
);
print @AoH;
print "
";
print $AoH[0]{husband};
print "
";
zjzc01:/root/big2# perl a21.pl 
HASH(0xb21d48)HASH(0xb3e590)HASH(0xb3e608)
barney


9.4  散列的散列:


多维的散列时Perl里面最灵活的嵌套结构。它就好像绑定一个记录,该记录本身包含其他记录。


在每个层次上,你都用一个字符(必要时引起)做该散列的索引。不过,你要记住散列里的键字/数值 对不会以任何特定的顺序出现,

你可以使用sort 函数以你喜欢的任何顺序检索这些配对。


9.4.1  构成一个散列的散列:

zjzc01:/root/big2# cat a22.pl 
%HoH = (
flintstones => {
husband => "fred",
pal => "barney",
},
jetsons => {
husband => "george",
wife => "jane",
"his boy" => "elroy", 
},
simpsons => {
husband => "homer",
wife => "marge",
kid => "bart",
}
);
print %HoH;
print "
";
print $HoH{flintstones}{husband};
print "
";
zjzc01:/root/big2# perl a22.pl 
simpsonsHASH(0x1700608)jetsonsHASH(0x17002c0)flintstonesHASH(0x16e3d48)
fred

9.5  函数的散列:

if ($cmd =~ /^exit$/i) { exit }
elsif ($cmd =~ /^help$/i) { show_help() }
elsif ($cmd =~ /^watch$/i) { $watch = 1 }
elsif ($cmd =~ /^mail$/i) { mail_msg($msg) }
elsif ($cmd =~ /^edit$/i) { $edited++; editmsg($msg); }
elsif ($cmd =~ /^delete$/i) { confirm_kill() }
else {
warn "Unknown command: `$cmd'; Try `help' next time
";
}

你还可以在你的数据结构里保存指向函数的引用,就像你可以存储指向数组或者散列的引用一样:


my (@frames,@button); 
        my %sub_of = ( 
    "日志查询" => &push_button2 , 
        "温金短信查询" => &push_button3 , 
        "中均短信查询" => &push_button4 , 
        "机器信息查询" => &push_button5, 
        "IP信息查询" => &push_button6, 
        "设备信息维护" => &push_button7, 
        "test" => sub{ print "program 6" }, 
        7 => sub{ print "program 7" }, 
        8 => sub{ print "program 8" }, 
        9 => sub{ print "program 9" }, 
);
~
第9章 数据结构

第9章数据结构
