Question

在perl中，最简单的方法是读取一个文件，一次说4行？

如果文件包含随机单词，如

bye
how
are
you
car
bed
dog

我想用大小为4的滑动窗口阅读文件，所以我想读一个字符串

bye how are you
how are you car
are you car bed
you car bed dog

Answer 1

这是另一个例子。每一行都被推送到数组@window，如果这导致数组中包含四个元素，则打印数组，并使用shift从头开始删除最旧的元素。

use strict;
use warnings;

my @window;

while (<DATA>) {
  chomp;
  push @window, $_;
  if (@window == 4) {
    print "@window\n";
    shift @window;
  }
}

__DATA__
bye
how
are
you
car
bed
dog

<强>输出

bye how are you
how are you car
are you car bed
you car bed dog

Answer 2

创建一个缓冲区，然后逐行处理;

use strict;
use warnings;

my @buffer = map {scalar <DATA>} (1..3);

while (<DATA>) {
    push @buffer, $_;

    # Show Buffer on a single line
    print join(' ', map {chomp; $_} @buffer), "\n";

    shift @buffer;
}

__DATA__
Line1
Line2
Line3
Line4
Line5
Lien6
Line7
Line8
Line9

输出：

Line1 Line2 Line3 Line4
Line2 Line3 Line4 Line5
Line3 Line4 Line5 Lien6
Line4 Line5 Lien6 Line7
Line5 Lien6 Line7 Line8
Lien6 Line7 Line8 Line9

<强>更新

要主动删除行结尾，请执行以下操作。输出将与上述相同：

my @buffer = map {$_ = <DATA>; chomp; $_} (1..3);

while (<DATA>) {
    chomp;
    push @buffer, $_;

    # Show Buffer
    print "@buffer\n";

    shift @buffer;
}

Answer 3

将单词加载到数组中，然后可以使用push和shift循环数组，并打印数组切片：

use strict;
use warnings;

chomp(my @words = <DATA>);

for (1 .. 4) {
    print "@words[0..3]\n";
    push @words, shift @words;
}


__DATA__
bye
how
are
you
car
bed
dog

<强>输出：

how are you car
are you car bed
you car bed dog
car bed dog bye

从文件中读取多行（作为滑动窗口）的最简单方法

3 个答案: