add python kyu6 kata

Author: streltcov

python/kyu5_calculate_variance.py

@@ -1,17 +1,14 @@
-def variance(numbers):
-    """ Write a function which will accept a sequence of numbers and calculate the variance for the sequence;
-    The variance for a set of numbers is found by subtracting the mean from every value, squaring the results, adding
-    them all up and dividing by the number of elements;
+""" Write a function which will accept a sequence of numbers and calculate the variance for the sequence;
+The variance for a set of numbers is found by subtracting the mean from every value, squaring the results, adding
+them all up and dividing by the number of elements;
+
+Examples:
+    variance([8, 9, 10, 11, 12]), 2)
+    variance([1.5, 2.5, 4, 2, 1, 1]), 1.0833333333333333)
 
-    Examples:
-        variance([8, 9, 10, 11, 12]), 2)
-        variance([1.5, 2.5, 4, 2, 1, 1]), 1.0833333333333333)
+"""
 
-    Args:
-        numbers: the sequence of numbers to calculate the variance for
 
-    Returns:
-        float: a variance for given sequence
-    """
+def variance(numbers):
     mean = sum(numbers) / len(numbers)
     return sum(list(map(lambda x: (x - mean) ** 2, numbers))) / len(numbers)

python/kyu5_number_of_trailing_zeros_of_N.py

@@ -1,23 +1,20 @@
-def zeros(n):
-    """ Write a program that will calculate the number of trailing zeros in a factorial of a given number;
-    N! = 1 * 2 * 3 * ... * N
-    Be careful 1000! has 2568 digits...
+""" Write a program that will calculate the number of trailing zeros in a factorial of a given number;
+N! = 1 * 2 * 3 * ... * N
+Be careful 1000! has 2568 digits...
+
+Hint: You're not meant to calculate the factorial. Find another way to find the number of zeros;
 
-    Hint: You're not meant to calculate the factorial. Find another way to find the number of zeros;
+Examples:
+    zeros(6) = 1
+    # 6! = 1 * 2 * 3 * 4 * 5 * 6 = 720 --> 1 trailing zero
 
-    Examples:
-        zeros(6) = 1
-        # 6! = 1 * 2 * 3 * 4 * 5 * 6 = 720 --> 1 trailing zero
+    zeros(12) = 2
+    # 12! = 479001600 --> 2 trailing zeros
 
-        zeros(12) = 2
-        # 12! = 479001600 --> 2 trailing zeros
+"""
 
-    Args:
-        n (int): the number in the factorial of which we want to count the number of trailing zeros;
 
-    Returns:
-        int: number of trailing zeros
-    """
+def zeros(n):
     count, i = 0, 5
     while n // i:
         count, i = count + n // i, i * 5

python/kyu6_array_diff.py

@@ -1,19 +1,15 @@
-def array_diff(a, b):
-    """ Your goal in this kata is to implement a difference function, which subtracts one list
-    from another and returns the result;
+""" Your goal in this kata is to implement a difference function, which subtracts one list
+from another and returns the result;
+
+It should remove all values from list a, which are present in list b;
+If a value is present in b, all of its occurrences must be removed from the other;
 
-    It should remove all values from list a, which are present in list b;
-    If a value is present in b, all of its occurrences must be removed from the other;
+Examples:
+    array_diff([1,2],[1]) == [2]
+    array_diff([1,2,2,2,3],[2]) == [1,3]
 
-    Examples:
-        array_diff([1,2],[1]) == [2]
-        array_diff([1,2,2,2,3],[2]) == [1,3]
+"""
 
-    Args:
-        a (list): first list
-        b (list): second list
 
-    Returns:
-        list: difference for lists 'a' and 'b'
-    """
+def array_diff(a, b):
     return [x for x in a if x not in b]

python/kyu6_the_vowel_code.py

@@ -15,20 +15,19 @@
 above
 For example, decode("h3 th2r2") would return "hi there"
 For the sake of simplicity, you can assume that any numbers passed into the function will correspond to vowels
+
 """
 
+vowels = {'a': 1, 'e': 2, 'i': 3, 'o': 4, 'u': 5, 'A': 1, 'E': 2, 'I': 3, 'O': 4, 'U': 5,}
+
 
 def encode(st):
-    encoded = ''
-    vowels = {'a': 1, 'e': 2, 'i': 3, 'o': 4, 'u': 5}
-    for char in st:
-        encoded += str(vowels[str(char).lower()]) if str(char).lower() in vowels.keys() else str(char)
-    return encoded
+    encode_char = lambda char: char if char not in vowels.keys() else str(vowels.get(char, ''))
+    return ''.join([encode_char(a) for a in st])
 
 
 def decode(st):
-    decoded = ''
-    numbers = {'1': 'a', '2': 'e', '3': 'i', '4': 'o', '5': 'u'}
-    for char in st:
-        decoded += str(numbers[str(char)]) if char in numbers.keys() else char
-    return decoded
+    inversed_vowels = {str(v): str(k) for k, v in vowels.items()}
+    decode_char = lambda char: char if char not in inversed_vowels.keys() else str(
+        inversed_vowels.get(char, '')).lower()
+    return ''.join([decode_char(a) for a in st])

python/kyu7_is_isogram.py

@@ -0,0 +1,14 @@
+""" An isogram is a word that has no repeating letters, consecutive or non-consecutive. Implement a function that
+determines whether a string that contains only letters is an isogram. Assume the empty string is an isogram;
+Ignore letter case;
+
+Example: (Input --> Output)
+    "Dermatoglyphics" --> true
+    "aba" --> false
+    "moOse" --> false (ignore letter case)
+
+"""
+
+
+def is_isogram(string):
+    return len(list(set(string.lower()))) == len(list(string.lower()))