Python3: Custom Sort

Question

I have dictionary and I want to sort frequency from highest to lowest. If two words have the same frequency, then the word with the lower alphabetical order comes first.

I wanted to use cmp function but apparently this function is deprecated in python 3.

This is what I've done:

    dic = {'i': 2, 'like': 2, 'so': 1, 'coding': 1}
    output = [key for key, value in sorted(
        dic.items(), key=itemgetter(1, 0), reverse=True)]

    print(output) // ['like', 'i', 'so', 'coding']

My desired output is ['i, 'like', 'coding', 'so' ]

Andrej Kesely · Accepted Answer · 2020-05-04 23:30:28Z

4

You can put - sign to first element in the sorting key to reverse the order:

dic = {'i': 2, 'like': 2, 'so': 1, 'coding': 1}

print([k for k, _ in sorted(dic.items(), key=lambda k: (-k[1], k[0]))])

Prints:

['i', 'like', 'coding', 'so']

answered May 4, 2020 at 23:30

Andrej Kesely

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3 Comments

Melchia Over a year ago

Thank you it's working. Just one more question please what if I want to sort descending alphabetically

user11697799 Over a year ago

Do you mean sort depending on alphabet when both have same size? I didn't understand the question clearly.

Andrej Kesely Over a year ago

@Melchia If you want to sort from highest frequency and descending alphabetically, then you can do sorted(dic.items(), key=lambda k: (k[1], k[0]), reverse=True), the output would be ['like', 'i', 'so', 'coding']

user11697799 · Accepted Answer · 2020-05-04 23:35:37Z

2

You can use key parameter in sorted. It will sort by value which is represented by x[1] else choose smallest size which is represented by -len(x[0])

output = [key for key,_ in sorted(dic.items(),key=lambda x: (x[1],-len(x[0])),reverse=True)]

Output:

['i', 'like', 'so', 'coding']

answered May 4, 2020 at 23:35

user11697799

2 Comments

Melchia Over a year ago

Actually it's alphabetically but Thanks I see how using the lambda is more powerful than itemgetter

user11697799 Over a year ago

Yes, in sort function you can provide a full function as key which is quite useful in a lot of cases.

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