如何获得特定单词恰好重复 N 次的行？

Question

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

获取整行只包含三个重复的“这个”词。（不区分大小写匹配）

Answer 1

在 中perl，this不区分大小写地替换为自身并计算替换次数：

$ 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 1。

Answer 2

在 python 中，这可以完成这项工作：

#!/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

或者从文件中读取，以文件为参数：

#!/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)

• 将脚本粘贴到一个空文件中，另存为find_3.py，通过命令运行它：

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

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

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

编辑

如果文件很大（数十万/百万行），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:
    lines = [line.strip() for line in src.readlines()]

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

Answer 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 输出在 tmp.txt 中没有 4 个或更多不区分大小写的“this”出现的所有行。

结果通过管道传送到右侧 grep，它输出左侧 grep 结果中出现 3 次或更多的所有行。

更新：感谢@Muru，这是此解决方案的更好版本，

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

用 n+1 替换 4，用 n 替换 3。

Answer 4

您可以awk为此玩一些：

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

• 我们所做的就是为自己定义字段分隔符this。这样，该行将具有与单词this出现次数一样多的字段 +1 。

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

• 然后，只需说NF==4让所有这些行都this恰好有 3 次。不需要更多代码，因为{print $0}（即打印当前行）是awk表达式计算结果为 时的默认行为True。

Answer 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