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αғsнιη
Asked: 2015-01-05 09:13:10 +0800 CST

如何获得特定单词恰好重复 N 次的行？

  • 772

对于这个给定的输入：

How to get This line that this word repeated 3 times in THIS line?
But not this line which is THIS word repeated 2 times.
And I will get This line with this here and This one
A test line with four this and This another THIS and last this

我想要这个输出：

How to get This line that this word repeated 3 times in THIS line?
And I will get This line with this here and This one

获取整行仅包含三个重复的“this”字样。（不区分大小写的匹配）

text-processing

7 个回答

  1. Best Answer

    在中，不区分大小写地perl替换为自身并计算替换次数：this

    $ perl -ne 's/(this)/$1/ig == 3 && print' <<EOF
How to get This line that this word repeated 3 times in THIS line?
But not this line which is THIS word repeated 2 times.
And I will get This line with this here and This one
A test line with four this and This another THIS and last this
EOF
How to get This line that this word repeated 3 times in THIS line?
And I will get This line with this here and This one

    改为使用匹配计数：

    perl -ne 'my $c = () = /this/ig; $c == 3 && print'

    如果你有 GNU awk，一个非常简单的方法：

    gawk -F'this' -v IGNORECASE=1 'NF == 4'

    字段数将比分隔符数多一个。

    • 13

  2. 在 python 中，这将完成这项工作： 

    #!/usr/bin/env python3

s = """How to get This line that this word repeated 3 times in THIS line?
But not this line which is THIS word repeated 2 times.
And I will get This line with this here and This one
A test line with four this and This another THIS and last this"""

for line in s.splitlines():
    if line.lower().count("this") == 3:
        print(line)

    输出：

    How to get This line that this word repeated 3 times in THIS line?
And I will get This line with this here and This one

    或者以文件作为参数从文件中读入：

    #!/usr/bin/env python3
import sys

file = sys.argv[1]

with open(file) as src:
    lines = [line.strip() for line in src.readlines()]

for line in lines:
    if line.lower().count("this") == 3:
        print(line)

    • 将脚本粘贴到一个空文件中，另存为find_3.py，通过命令运行：

      python3 /path/to/find_3.py <file_withlines>

    当然单词“this”可以替换为任何其他单词（或其他字符串或行部分），并且每行出现的次数可以设置为该行中的任何其他值：

        if line.lower().count("this") == 3:

    编辑

    如果文件很大（数十万/数百万行），下面的代码会更快；它每行读取文件而不是一次加载文件：

    #!/usr/bin/env python3
import sys
file = sys.argv[1]

with open(file) as src:
    for line in src:
        if line.lower().count("this") == 3:
            print(line.strip())
    • 9

  3. 假设你的源文件是 tmp.txt，

    grep -iv '.*this.*this.*this.*this' tmp.txt | grep -i '.*this.*this.*this.*'

    左边的 grep 输出所有在 tmp.txt 中没有出现 4 次或更多次不区分大小写的“this”的行。

    结果通过管道传输到右侧 grep，它输出在左侧 grep 结果中出现 3 次或更多次的所有行。

    更新：感谢@Muru，这是这个解决方案的更好版本， 

    grep -Eiv '(.*this){4,}' tmp.txt | grep -Ei '(.*this){3}'

    将 4 替换为 n+1，将 3 替换为 n。

    • 9

  4. 你可以玩一下awk这个：

    awk -F"this" 'BEGIN{IGNORECASE=1} NF==4' file

    这将返回：

    How to get This line that this word repeated 3 times in THIS line?
And I will get This line with this here and This one

    解释

    • 我们所做的是为其this自身定义字段分隔符。这样，该行将具有与单词this出现次数一样多的 +1 字段。

    • 为了使其不区分大小写，我们使用IGNORECASE = 1. 请参阅参考资料：匹配中的区分大小写。

    • 然后，只需要说NF==4得到所有那些this正好有 3 次的行。不需要更多代码，因为{print $0}（即打印当前行）是awk表达式求值为 时的默认行为True。

    • 6

  5. 假设这些行存储在一个名为的文件中FILE：

    while read line; do 
    if [ $(grep -oi "this" <<< "$line" | wc -w)  = 3 ]; then 
        echo "$line"; 
    fi  
done  <FILE
    • 5

  6. 如果你在 Vim 中：

    g/./if len(split(getline('.'), 'this\c', 1)) == 4 | print | endif

    这只会打印匹配的行。

    • 4

  7. Ruby 单行解决方案：

    $ ruby -ne 'print $_ if $_.chomp.downcase.scan(/this/).count == 3' < input.txt                                    
How to get This line that this word repeated 3 times in THIS line?
And I will get This line with this here and This one

    以一种非常简单的方式工作：我们将文件重定向到 ruby​​ 的标准输入，ruby 从标准输入获取行，用chompand清理它downcase，并scan().count给我们一个子字符串的出现次数。

    • 0

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