Skip to content

192. Word Frequency

Description

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?

Solutions

Solution 1: awk

Thinking

Word frequencies, most common first. Squeeze spaces to newlines so each word is a line, sort, then \(\textit{uniq}\,-c\). Sort those counts numerically descending, and \(\textit{awk}\) swaps “count word” into “word count”.

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

Comments