192 Word Frequency

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.

[show hint]

Hint:
Could you write it in one-line using Unix pipes?

 

#!/usr/bin/env bash

declare -A HashWord
File="words.txt"

function ReadTxtFile
{
    while read Line
    do
        Word=(${Line})
        for Var in ${Word[@]}
        do
            HashWord+=( [${Var}]='1')
            Word[${Var}]=
            for i in ${Word[@]}
            do
                if [[ ${Var} == ${i} ]];then
                    Value=${HashWord[${Var}]}
                fi
            done

        done
    done < ${File}


    for Key in ${!HashWord[*]}
    do
        echo "${Key} ${#HashWord[${Key}]}"
    done
}


### Main Logic

ReadTxtFile

 

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.