Leetcode: Word Frequency

Question

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.

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My Solution

using array in awk is common to use

awk ‘{for(i=1;i<=NF;i++){arr[$i] +=1;}} END{for(i in arr){print i,arr[i] | “sort -nr -k2”};}’ words.txt

If using pipeline,

awk ‘{for(i=1;i<=NF;i++){arr[$i] +=1;}} END{for(i in arr){print i,arr[i] }’ words.txt | sort -nr -k2

sort -r: in reverse order, -k2: sort in the second column

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Other′s Solution

cat words.txt | tr -s ′ ′ ′\n′ | sort | uniq -c | sort -rn | awk ‘{print $2″ ″$1}’

tr -s ′ ′ ′\n′: substitute ′\n′ for ′ ′
uniq -c: count the same one