[LeetCode]Word Frequency

题目描述:

Write a bash script to calculate the frequency of each word in a text file words.txt.

For simplicity sake, you may assume:

  • words.txt contains only lowercase characters and space ' ' characters.
  • Each word must consist of lowercase characters only.
  • Words are separated by one or more whitespace characters.

For example, assume that words.txt has the following content:

the day is sunny the the
the sunny is is

Your script should output the following, sorted by descending frequency:

the 4
is 3
sunny 2
day 1

Note:

Don't worry about handling ties, it is guaranteed that each word's frequency count is unique.

题目大意:

编写一段bash脚本计算文本文件words.txt中每个单词的频度。

为了使问题简化,你可以做如下假设:

  • words.txt中只包含小写字母和空格
  • 每一个单词只由小写字母组成
  • 单词之间以一个或者多个空格分隔

例如,假设words.txt包含下面的内容:

the day is sunny the the
the sunny is is

你的脚本应该输出下面的结果,按照单词频度倒序排列:

the 4
is 3
sunny 2
day 1

注意:

无需考虑并列排名的情况,测试样例确保每一个单词的频度都是唯一的。

Bash脚本:

参阅:https://leetcode.com/discuss/29049/my-simple-solution-one-line-with-pipe

# Read from the file words.txt and output the word frequency list to stdout.
cat words.txt | tr -s ' ' '\n' | sort | uniq -c | sort -rn | awk '{print $2" "$1}'

tr -s: 使用指定字符串替换出现一次或者连续出现的目标字符串(把一个或多个连续空格用换行符代替)

sort: 将单词从小到大排序

uniq -c: uniq用来对连续出现的行去重,-c参数为计数

sort -rn: -r 倒序排列, -n 按照数值大小排序(感谢网友 长弓1990 指正)

awk '{ print $2, $1 }': 格式化输出,将每一行的内容用空格分隔成若干部分,$i为第i个部分。

本文链接:http://bookshadow.com/weblog/2015/03/24/leetcode-word-frequency/
请尊重作者的劳动成果,转载请注明出处!书影博客保留对文章的所有权利。

如果您喜欢这篇博文,欢迎您捐赠书影博客: ,查看支付宝二维码