collections.defaultdict clear solution for The Most Wanted Letter by David_Jones - python coding challenges

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collections.defaultdict solution in Clear category for The Most Wanted Letter by David_Jones

from collections import defaultdict

def checkio(text):
    d = defaultdict(int)
    for ch in text.lower():
        if ch.isalpha():
            d[ch] += 1
    return max(d.items(), key=lambda x: (x[1], -ord(x[0])))[0]

May 2, 2019

Comments:

ecarloshanson on June 16, 2019, 8:38 a.m.
This is an interesting solution. I really like the use of defaultdict. Clearly, I need to dig into collections. I regularly use the following: <pre class='brush: python'>d = {} d[ch] = d.get(ch, 0) + 1 </pre> I have no idea how you came up with the return statement. After playing with it, I see how it works, but that is definitely not intuitive for me. Thanks for sharing.

David_Jones on June 16, 2019, 9:46 a.m.
Thank you. The common way to sort would be <pre class='brush: python'>key=lambda x: (x[1], x[0]) </pre> However, we need to return the letter which comes FIRST in the latin alphabet. So <pre class='brush: python'>-ord(x[0]) </pre> kind of reverses the second level of sorting. PS: if x[0] was int, it would be simpler: <pre class='brush: python'>key=lambda x: (x[1], -x[0]) </pre>

Strings and Integers

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