分析

写bash，不太会啊……

难度 中

来源

https://leetcode.com/problems/word-frequency/

题目

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.

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.
• Could you write it in one-line using Unix pipes?

解答

https://leetcode.com/problems/word-frequency/discuss/55443/My-simple-solution-(one-line-with-pipe)

 cat words.txt | tr -s ' ' '\n' | sort | uniq -c | sort -r | awk '{ print $2, $1 }'

tr -s: truncate the string with target string, but only remaining one instance (e.g. multiple whitespaces)

sort: To make the same string successive so that uniq could count the same string fully and correctly.

uniq -c: uniq is used to filter out the repeated lines which are successive, -c means counting

sort -r: -r means sorting in descending order

awk '{ print $2, $1 }': To format the output, see here.