code-katas

CodeWars Assignments for Snow Day.

Convert a String to an Array (8 kyu)

• Module:string_to_array.py
• Tests: test_string_to_array.py
• Link: https://www.codewars.com/kata/convert-a-string-to-an-array/train/python
• Interesting/simplest Solution: I didn't think to add the space in the .split().

def string_to_array(string):
    """Solution by jerod84."""
    return string.split(" ")
    

Last (8 kyu)

• Module: last.py
• Tests: test_last.py
• Link: https://www.codewars.com/kata/last/train/python
• Interesting Solution: I love try/except. It's so simple.

def last(*args):
    """Solution by jake9066."""
    try:
        return args[-1][-1]
    except:
        return args[-1]

Fake Binary (8 kyu)

• Module: fake_binary.py
• Tests: fake_binary.py
• Link: https://www.codewars.com/kata/fake-binary
• Interesting Solution:

def fake_bin(s):
    """Solution by PilgrimShadow."""
  return ''.join('0' if int(c) < 5 else '1' for c in s)

Count of positives / sum of negatives (8 kyu)

• Module: count_positives_sum_negatives.py
• Tests: test_count_positives_sum_negatives.py
• Link: https://www.codewars.com/kata/count-of-positives-slash-sum-of-negatives/train/python
• Interesting Solution: I think these ternaries are interesting but I'm not sure I like them. I think they're kind of hard to read. Are they more pythonic than ifs and fors?

def count_positives_sum_negatives(arr):
    """Solution by j.pihlgren."""
    return [len([x for x in arr if x > 0])] + [sum(y for y in arr if y < 0)] if arr else []

Convert number to reversed array of digits (8 kyu)

• Module: digitize.py
• Tests: test_digitize.py
• Link: https://www.codewars.com/kata/convert-number-to-reversed-array-of-digits/train/python
• Interesting Solution: I liked map functions in js but am not yet used to them in python.

def digitize(n):
    """Solution by colbydauph."""
    return map(int, str(n)[::-1])

Ones and zeros (8 kyu)

• Module: binary_list_to_number.py
• Tests: test_list_array_to_number.py
• Link: https://www.codewars.com/kata/ones-and-zeros/train/python
• Interesting Solution: Still love that map. Didn't know about the binary optional argument in int(). That's cool.

def binary_array_to_number(arr):
    """Solution by andrewferk."""
    return int("".join(map(str, arr)), 2)

Holiday V - SeaSick Snorkelling (7 kyu)

• Module: sea_sick.py
• Tests: test_sea_sick.py
• Link: https://www.codewars.com/kata/holiday-v-seasick-snorkelling/train/python
• Interesting Solution: Another simple ternary. I think this one is easy to read and clear.

def sea_sick(sea):
    """Solution by kevin.du."""
    return "Throw Up" if (sea.count("~_") + sea.count("_~")) > 0.2*len(sea) else "No Problem"

String Reversing, Changing case, etc. (7 kyu)

• Module: reverse_and_mirror.py
• Tests: test_reverse_and_mirror.py
• Link: https://www.codewars.com/kata/string-reversing-changing-case-etc/train/python
• Interesting Solution: Simple ternary. I think this one is even clearer and easier to read.

def reverseAndMirror(s1,s2):
    """Solution by dkleist."""
    return s2.swapcase()[::-1] + '@@@' + s1.swapcase()[::-1] + s1.swapcase()

Flatten Me (7 kyu)

• Module: flatten_me.py
• Tests: test_flatten_me.py
• Link: https://www.codewars.com/kata/flatten-me/train/python
• Interesting Solution: I'm hoping that if I look at enough of these ternaries I'll start using them.

def flatten_me(lst):
    """Soltion by daddepledge."""
    return [v for sub in [e if type(e) == list else [e] for e in lst] for v in sub]

Sum up the random string (7 kyu)

• Module: sum_from_string.py
• Tests: test_sum_from_string.py
• Link: https://www.codewars.com/kata/sum-up-the-random-string/train/python
• Interesting Solution: I spent some time trying to do it this way, but I come up short figuring out the regex.

import re
def sum_from_string(string):
    """Solution by JustFY."""
    d = re.findall("\d+",string)
    return sum(int(i) for i in d)

Show multiples of 2 numbers within a range (7 kyu)

• Module: multiples.py
• Tests: test_multiples.py
• Link: https://www.codewars.com/kata/show-multiples-of-2-numbers-within-a-range/train/python
• Interesting Solution: I like that they used not a % s1. I didnt think to use a not with modulus but it makes so much sense. Will do that in the future.

def multiples(s1, s2, s3):
    """Solution by zebulan."""
    return [a for a in xrange(1, s3) if not(a % s1 or a % s2)]