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perl实例分析教程之六
来源:linux宝库作者:linux宝库 发布时间:2007-09-30 00:00:00


  3、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)

  .用于实数

  (2.1..5.3) = (2.1, 3.1 ,4.1, 5.1)

  (4.5..1.6) = ()

  .用于字符串

  ("aaa".."aad") = ("aaa","aab", "aac", "aad")

  @day_of_month = ("01".."31")

  .可包含变量或表达式

  ($var1..$var2+5)

  .小技巧:

  $fred = "Fred";

  print (("Hello, " . $fred . "!n") x 2);

  其结果为:

  Hello, Fred!

  Hello, Fred!

  4、数组的输出:

  (1) @array = (1, 2, 3);

  print (@array, "n");

  结果为:

  123

  (2) @array = (1, 2, 3);

  print ("@arrayn");

  结果为:

  1 2 3

  5、列表/数组的长度

  当数组变量出现在预期简单变量出现的地方,则PERL解释器取其长度。

  @array = (1, 2, 3);

  $scalar = @array; # $scalar = 3,即@array的长度

  ($scalar) = @array; # $scalar = 1,即@array第一个元素的值

  注:以数组的长度为循环次数可如下编程:

  $count = 1;

  while ($count <= @array) {

  print ("element $count: $array[$count-1]n");

  $count++;

  }

  6、子数组

  @array = (1, 2, 3, 4, 5);

  @subarray = @array[0,1]; # @subarray = (1, 2)

  @subarray2 = @array[1..3]; # @subarray2 = (2,3,4)

  @array[0,1] = ("string", 46); # @array =("string",46,3,4,5) now

  @array[0..3] = (11, 22, 33, 44); # @array = (11,22,33,44,5) now

  @array[1,2,3] = @array[3,2,4]; # @array = (11,44,33,5,5) now

  @array[0..2] = @array[3,4]; # @array = (5,5,"",5,5) now

  能够用子数组形式来交换元素:

  @array[1,2] = @array[2,1];

  7、有关数组的库函数

  (1)sort--按字符顺序排序

  @array = ("this", "is", "a","test");

  @array2 = sort(@array); # @array2 = ("a","is", "test", "this")

  @array = (70, 100, 8);

  @array = sort(@array); # @array = (100, 70, 8) now

  (2)reverse--反转数组

  @array2 = reverse(@array);

  @array2 = reverse sort (@array);

  (3)chop--数组去尾

  chop的意义是去掉STDIN(键盘)输入字符串时最后一个字符--换行符。而假如他作用到数组上,则将数组中每一个元素都做如此处理。

  @list = ("rabbit", "12345","quartz");

  chop (@list); # @list = ("rabbi", "1234","quart") now

  (4)join/split--连接/拆分

  join的第一个参数是连接所用的中间字符,其余则为待连接的字符数组。

  $string = join(" ", "this", "is","a", "string"); # 结果为"this is a string"

  @list = ("words","and");

  $string = join("::", @list, "colons"); #结果为"words::and::colons"

  @array = split(/::/,$string); # @array = ("words","and", "colons") now

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