Perl入门（四）－－列表和数组

多个变量可以用圆括号组合成列表，并可以赋给数组变量。数组变量用@varname表示。下面是数组的一些基本操作：

@array = (32, "hello", 82.1);

$value = @array[0]; # 32
@array[2] = 12.8; # 32 hello 12.8
$value = @array[4]; # null
@array[5] = "ok"; # 32 hello 12.8 "" ok

@array_copy = @array;
@array_new = (1, @array, 5); # 1 32 hello 12.8 "" ok 5

列表和数组之间可以相互赋值：

@array = (1, 2, 3);
($var1, $var2) = @array; # $var1=1, $var2=2
($var1, $var2, $var3, $var4) = @array; # $var4=null
($var1, @array2) = @array; #$var1=1, @array2=(2,3)
(@array1, $var2) = @array; #@array1=(1,2,3), $var2=null

字符串中的数组变量：

@array = (1, 2, 3);
$array = "a";
print "@array[0]\n"; # 1
print "\@array[0]\n"; # @array[0]
print "$array[0]\n"; # 1
print "$array\[0]\n"; # a[0] 等价于$array . "[0]"
print "${array}[0]\n"; # a[0] 等价于$array . "[0]"
print "$\{array}[0]\n"; # 输出两个空行。

 

列表范围：

(1..10) = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
    (2, 5..7, 11) = (2, 5, 6, 7, 11)
    (3..3) = (3)
    (2.1..5.3) = (2.1, 3.1 ,4.1, 5.1)
    (4.5..1.6) = ()
    ("aaa".."aad") =("aaa","aab", "aac","aad")
    @day_of_month =("01".."31")

可包含变量或表达式

($var1..$var2+5)

数组的长度：

   

$length = @array; 或 $length = scalar(@array)

子数组：

@array = (1, 2, 3, 4, 5);
@sub_array = @array[1,2,4]; # (2, 3, 5)
@array[2..4] = ("x", "y", "z"); # (1, 2, "x", "y", "z")
@array[1, 0] = @array[4,3]; # ("y", "z", "x", "y", "z")

数组函数：
sort用来（以字母序）排序，reverse用来反转数组，chop用来清除数组内所有元素字符串的最后一个字符，join用来把数组连接为字符串，split用来把字符串拆分为数组：

@array = ("ax", "zb", "ac", "xhh", "dxy");
@array2 = sort @array; # ("ac" "ax" "dxy" "xhh" "zb")
@array2 = reverse @array; # (dxy xhh ac zb ax)
@array2 = reverse sort @array; # (zb xhh dxy ax ac)

@array = (83, 76, 102, 908);
@array2 = sort @array; # (102 76 83 908) 按字母序排序

@array = ("abc", "def", 123, 456, 7.89);
chop @array; # (ab de 12 45 7,8)

$string = join(" ", "joined", "by", "space"); # joined by space
$string = join("-", "joined", "by", "hyphen"); # joined-by-hyphen
@array = ("two", "three");
$string = join("::", "one", @array, "four"); # one::two::three::four

@array = split(/~/, "1~2~3~4"); # 1 2 3 4