Session 4 - Natallia Paliashchuk

NatalliaPaliashchuk/hw2.py

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+# Homework-4_Python-Functions.md
+# Совместный доступ
+# P
+# Свойства системы
+# Тип
+# Текст
+# Размер
+# 4 КБ
+# Занимает
+# 4 КБ
+# Расположение
+# Session 4
+# Владелец
+# Python Training
+# Изменено
+# 20 апр. 2022 г. (Python Training)
+# Открыто
+# 22:01 (я)
+# Создано"
+# 20 апр. 2022 г.
+# Описания нет
+# Читателям разрешено скачивать файл
+# # Python Practice - Session 4
+
+
+# ### Task 4.1
+# Implement a function which receives a string and replaces all `"` symbols
+# with `'` and vise versa.
+def replacer(str_):
+    table = str_.maketrans("'\"", "\"'")
+    return str_.translate(table)
+
+
+
+# ### Task 4.2
+# Write a function that check whether a string is a palindrome or not. Usage of
+# any reversing functions is prohibited. To check your implementation you can use
+# strings from [here](https://en.wikipedia.org/wiki/Palindrome#Famous_palindromes).
+def palindrom_checker(str_): return str_[::-1].upper() == str_.upper()
+
+# ### Task 4.3
+# Implement a function which works the same as `str.split` method
+# (without using `str.split` itself, ofcourse).
+def str_split(s, sep=None):
+    if sep is None:
+        sep = ' '
+    list_, prvs = [], 0
+    for indx, _ in enumerate(s):
+        if _ == sep and s[indx - 1] != sep:
+            list_.append(s[prvs:indx])
+            prvs = indx + 1
+        elif s[indx - 1] == sep:
+            prvs = indx
+    if s[prvs:]:
+        list_.append(s[prvs:])
+    return list_
+
+# ### Task 4.4
+# Implement a function `split_by_index(s: str, indexes: List[int]) -> List[str]`
+# which splits the `s` string by indexes specified in `indexes`. Wrong indexes
+# must be ignored.
+# Examples:
+# ```python
+# >>> split_by_index("pythoniscool,isn'tit?", [6, 8, 12, 13, 18])
+# ["python", "is", "cool", ",", "isn't", "it?"]
+
+# >>> split_by_index("no luck", [42])dx
+# ["no luck"]
+# ```
+def split_by_index(s, indexes):
+    list_, prvs = [], 0
+    for indx, _ in enumerate(s):
+        if indx in indexes:
+            list_.append(s[prvs:indx])
+            prvs = indx
+    list_.append(s[prvs:])
+
+    return list_
+
+# ### Task 4.5
+# Implement a function `get_digits(num: int) -> Tuple[int]` which returns a tuple
+# of a given integer's digits.
+# Example:
+# ```python
+# >>> split_by_index(87178291199)
+# (8, 7, 1, 7, 8, 2, 9, 1, 1, 9, 9)
+# ```
+def get_digits(num):
+    return tuple(int(digit) for digit in str(num))
+
+# ### Task 4.6
+# Implement a function `get_shortest_word(s: str) -> str` which returns the
+# longest word in the given string. The word can contain any symbols except
+# whitespaces (` `, `\n`, `\t` and so on). If there are multiple longest words in
+# the string with a same length return the word that occures first.
+# Example:
+# ```python
+def get_shortest_word(s):
+    return max(s.split(), key=lambda word: len(word))
+
+
+# >>> get_shortest_word('Python is simple and effective!')
+# 'effective!'
+
+# >>> get_shortest_word('Any pythonista like namespaces a lot.')
+# 'pythonista'
+# ```
+
+# ### Task 4.7
+# Implement a function `foo(List[int]) -> List[int]` which, given a list of
+# integers, return a new list such that each element at index `i` of the new list
+# is the product of all the numbers in the original array except the one at `i`.
+# Example:
+# ```python
+# >>> foo([1, 2, 3, 4, 5])
+# [120, 60, 40, 30, 24]
+
+# >>> foo([3, 2, 1])
+# [2, 3, 6]
+# ```
+def foo(list_):
+    from math import prod
+    prod_ = prod(list_) 
+    return [prod_ // digit for digit in list_]
+
+# ### Task 4.8
+# Implement a function `get_pairs(lst: List) -> List[Tuple]` which returns a list
+# of tuples containing pairs of elements. Pairs should be formed as in the
+# example. If there is only one element in the list return `None` instead.
+# Example:
+# ```python
+# >>> get_pairs([1, 2, 3, 8, 9])
+# [(1, 2), (2, 3), (3, 8), (8, 9)]
+
+# >>> get_pairs(['need', 'to', 'sleep', 'more'])
+# [('need', 'to'), ('to', 'sleep'), ('sleep', 'more')]
+
+# >>> get_pairs([1])val
+# None
+# ```
+def get_pairs(lst):
+    return [(value, lst[index + 1]) for index, value in enumerate(lst[:-1])] 
+
+
+# ### Task 4.9
+# Implement a bunch of functions which receive a changeable number of strings and return next parameters:
+
+# 1) characters that appear ingsstrin all strings
+
+# 2) characters that appear in at least one string
+
+# 3) characters that appear at least in two strings
+
+# 4) characters of alphabet, that were not used in any string
+
+# Note: use `string.ascii_lowercase` for list of alphabet letters
+
+# ```python
+# test_strings = ["hello", "world", "python", ]
+# print(test_1_1(*strings))
+# >>> {'o'}
+def test_1_1(*strings):
+    return set(''.join(strings)).intersection(*strings)
+
+# print(test_1_2(*strings))
+# >>> {'d', 'e', 'h', 'l', 'n', 'o', 'p', 'r', 't', 'w', 'y'}
+def test_1_2(*strings):
+    return set(''.join(strings))
+# print(test_1_3(*strings))
+# >>> {'h', 'l', 'o'}
+# print(test_1_4(*strings))
+# >>> {'a', 'b', 'c', 'f', 'g', 'i', 'j', 'k', 'm', 'q', 's', 'u', 'v', 'x', 'z'}
+def test_1_4(*strings):
+    from string import ascii_lowercase
+    return set(ascii_lowercase).difference(*strings)
+# ```
+
+# ### Task 4.10
+# Implement a function that takes a number as an argument and returns a dictionary, where the key is a number and the value is the square of that number.
+# ```python
+# print(generate_squares(5))
+# >>> {1: 1, 2: 4, 3: 9, 4: 16, 5: 25}
+# ```
+def generate_squares(num):
+    return {index: index**2 for index in range(1, num+1)}
+
+# ### Task 4.11
+# Implement a function, that receives changeable number of dictionaries (keys - letters, values - numbers) and combines them into one dictionary.
+# Dict values ​​should be summarized in case of identical keys
+
+# ```python
+# def combine_dicts(*args):
+#     ...
+
+# dict_1 = {'a': 100, 'b': 200}
+# dict_2 = {'a': 200, 'c': 300}
+# dict_3 = {'a': 300, 'd': 100}
+
+# print(combine_dicts(dict_1, dict_2)
+# >>> {'a': 300, 'b': 200, 'c': 300}
+
+
+# print(combine_dicts(dict_1, dict_2, dict_3)
+# >>> {'a': 600, 'b': 200, 'c': 300, 'd': 100}
+# ```
+def combine_dicts(*args):
+    result = {}
+    for dict_ in args:
+        for key, value in dict_.items():
+            result[key] = value + result.get(key, 0)
+    return result
+
+
+# ### Materials
+# * [Scope](https://python-scripts.com/scope)
+# * [Functions](https://python-scripts.com/functions-python)
+# * [Defining your own python function](https://realpython.com/defining-your-own-python-function/)
+# * [Python Lambda](https://realpython.com/python-lambda/)