Initial version taken from exercism/python

Author: reingart

LICENSE

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+MIT License
+
+Copyright (c) 2021 Exercism
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

accumulate/accumulate.py

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+def accumulate(collection, operation):
+    pass

accumulate/accumulate_test.py

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+import unittest
+
+from accumulate import accumulate
+
+
+class AccumulateTest(unittest.TestCase):
+    def test_empty_sequence(self):
+        self.assertEqual(accumulate([], lambda x: x / 2), [])
+
+    def test_pow(self):
+        self.assertEqual(
+            accumulate([1, 2, 3, 4, 5], lambda x: x * x), [1, 4, 9, 16, 25])
+
+    def test_divmod(self):
+        self.assertEqual(
+            accumulate([10, 17, 23], lambda x: divmod(x, 7)),
+            [(1, 3), (2, 3), (3, 2)])
+
+    def test_composition(self):
+        inp = [10, 17, 23]
+        self.assertEqual(
+            accumulate(
+                accumulate(inp, lambda x: divmod(x, 7)),
+                lambda x: 7 * x[0] + x[1]), inp)
+
+    def test_capitalize(self):
+        self.assertEqual(
+            accumulate(['hello', 'world'], str.upper), ['HELLO', 'WORLD'])
+
+    def test_recursive(self):
+        inp = ['a', 'b', 'c']
+        out = [['a1', 'a2', 'a3'], ['b1', 'b2', 'b3'], ['c1', 'c2', 'c3']]
+        self.assertEqual(
+            accumulate(
+                inp, lambda x: accumulate(list('123'), lambda y: x + y)), out)
+
+
+if __name__ == '__main__':
+    unittest.main()

accumulate/instructions.md

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+# Instructions
+
+Implement the `accumulate` operation, which, given a collection and an operation to perform on each element of the collection, returns a new collection containing the result of applying that operation to each element of the input collection.
+
+Given the collection of numbers:
+
+- 1, 2, 3, 4, 5
+
+And the operation:
+
+- square a number (`x => x * x`)
+
+Your code should be able to produce the collection of squares:
+
+- 1, 4, 9, 16, 25
+
+Check out the test suite to see the expected function signature.
+
+## Restrictions
+
+Keep your hands off that collect/map/fmap/whatchamacallit functionality provided by your standard library!
+Solve this one yourself using other basic tools instead.

acronym/acronym.py

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+def abbreviate(words):
+    pass

acronym/acronym_test.py

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+# These tests are auto-generated with test data from:
+# https://github.com/exercism/problem-specifications/tree/main/exercises/acronym/canonical-data.json
+# File last updated on 2023-07-20
+
+import unittest
+
+from acronym import (
+    abbreviate,
+)
+
+
+class AcronymTest(unittest.TestCase):
+    def test_basic(self):
+        self.assertEqual(abbreviate("Portable Network Graphics"), "PNG")
+
+    def test_lowercase_words(self):
+        self.assertEqual(abbreviate("Ruby on Rails"), "ROR")
+
+    def test_punctuation(self):
+        self.assertEqual(abbreviate("First In, First Out"), "FIFO")
+
+    def test_all_caps_word(self):
+        self.assertEqual(abbreviate("GNU Image Manipulation Program"), "GIMP")
+
+    def test_punctuation_without_whitespace(self):
+        self.assertEqual(abbreviate("Complementary metal-oxide semiconductor"), "CMOS")
+
+    def test_very_long_abbreviation(self):
+        self.assertEqual(
+            abbreviate(
+                "Rolling On The Floor Laughing So Hard That My Dogs Came Over And Licked Me"
+            ),
+            "ROTFLSHTMDCOALM",
+        )
+
+    def test_consecutive_delimiters(self):
+        self.assertEqual(abbreviate("Something - I made up from thin air"), "SIMUFTA")
+
+    def test_apostrophes(self):
+        self.assertEqual(abbreviate("Halley's Comet"), "HC")
+
+    def test_underscore_emphasis(self):
+        self.assertEqual(abbreviate("The Road _Not_ Taken"), "TRNT")

acronym/instructions.md

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+# Instructions
+
+Convert a phrase to its acronym.
+
+Techies love their TLA (Three Letter Acronyms)!
+
+Help generate some jargon by writing a program that converts a long name like Portable Network Graphics to its acronym (PNG).
+
+Punctuation is handled as follows: hyphens are word separators (like whitespace); all other punctuation can be removed from the input.
+
+For example:
+
+| Input                     | Output |
+| ------------------------- | ------ |
+| As Soon As Possible       | ASAP   |
+| Liquid-crystal display    | LCD    |
+| Thank George It's Friday! | TGIF   |

acronym/introduction.md

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+# Introduction
+
+There are multiple Pythonic ways to solve the Acronym exercise.
+Among them are:
+
+- Using `str.replace()` to scrub the input, and:
+  - joining with a `for loop` with string concatenation via the `+` operator.
+  - joining via `str.join()`, passing a `list-comprehension` or `generator-expression`.
+  - joining via `str.join()`,  passing `map()`.
+  - joining via `functools.reduce()`.
+
+- Using `re.findall()`/`re.finditer()` to scrub the input, and:
+  - joining via `str.join()`, passing a `generator-expression`.
+
+ - Using `re.sub()` for both cleaning and joining (_using "only" regex for almost everything_)`
+
+
+## General Guidance
+
+The goal of the Acronym exercise is to collect the first letters of each word in the input phrase and return them as a single capitalized string (_the acronym_).
+The challenge is to efficiently identify and capitalize the first letters while removing or ignoring non-letter characters such as `'`,`-`,`_`, and white space.
+
+
+There are two idiomatic strategies for non-letter character removal:
+- Python's built-in [`str.replace()`][str-replace].
+- The [`re`][re] module, (_regular expressions_).
+
+For all but the most complex scenarios, using `str.replace()` is generally more efficient than using a regular expression.
+
+
+Forming the final acronym is most easily done with a direct or indirect `loop`, after splitting the input into a word list via [`str.split()`][str-split].
+The majority of these approaches demonstrate alternatives to the "classic" looping structure using various other iteration techniques.
+Some `regex` methods can avoid looping altogether, although they can become very non-performant due to excessive backtracking.
+
+Strings are _immutable_, so any method to produce an acronym will be creating and returning a new `str`.
+
+
+## Approach: scrub with `replace()` and join via `for` loop
+
+```python
+def abbreviate(to_abbreviate):
+    phrase = to_abbreviate.replace('-', ' ').replace('_', ' ').upper().split()
+    acronym = ''
+    
+    for word in phrase:
+        acronym += word[0]
+
+    return acronym
+```
+
+For more information, take a look at the [loop approach][approach-loop].
+
+
+## Approach: scrub with `replace()` and join via `list comprehension` or `Generator expression`
+
+
+```python
+def abbreviate(to_abbreviate):
+    phrase = to_abbreviate.replace('-', ' ').replace('_', ' ').upper().split()
+    
+    return ''.join([word[0] for word in phrase])
+    
+###OR### 
+    
+def abbreviate(to_abbreviate):
+    phrase = to_abbreviate.replace('-', ' ').replace('_', ' ').upper().split()
+    
+    # note the parenthesis instead of square brackets.    
+    return ''.join((word[0] for word in phrase))
+```
+
+For more information, check out the [list-comprehension][approach-list-comprehension]  approach or the [generator-expression][approach-generator-expression] approach.
+
+
+## Approach: scrub with `replace()` and join via `map()`
+
+```python
+def abbreviate(to_abbreviate):
+    phrase = to_abbreviate.replace("_", " ").replace("-", " ").upper().split()
+    
+    return ''.join(map(lambda word: word[0], phrase))
+```
+
+For more information, read the [map][approach-map-function] approach.
+
+
+## Approach: scrub with `replace()` and join via `functools.reduce()`
+
+```python
+from functools import reduce
+
+
+def abbreviate(to_abbreviate):
+    phrase = to_abbreviate.replace("_", " ").replace("-", " ").upper().split()
+    
+    return reduce(lambda start, word: start + word[0], phrase, "")
+```
+
+For more information, take a look at the [functools.reduce()][approach-functools-reduce] approach.
+
+
+## Approach: filter with `re.findall()` and join via `str.join()`
+
+```python
+import re
+
+
+def abbreviate(phrase):
+    removed = re.findall(r"[a-zA-Z']+", phrase)
+    
+    return ''.join(word[0] for word in removed).upper()
+```
+
+For more information, take a look at the [regex-join][approach-regex-join] approach.
+
+
+## Approach: use `re.sub()`
+
+```python
+import re
+
+
+def abbreviate_regex_sub(to_abbreviate):
+    pattern = re.compile(r"(?<!_)\B[\w']+|[ ,\-_]")
+ 
+    return  re.sub(pattern, "", to_abbreviate.upper())
+```
+
+For more information, read the [regex-sub][approach-regex-sub] approach.
+
+
+## Other approaches
+
+Besides these seven idiomatic approaches, there are a multitude of possible variations using different string cleaning and joining methods.
+
+However, these listed approaches cover the majority of 'mainstream' strategies.
+
+
+## Which approach to use?
+
+All seven approaches are idiomatic, and show multiple paradigms and possibilities.
+All approaches are also `O(n)`, with `n` being the length of the input string.
+No matter the removal method, the entire input string must be iterated through to be cleaned and the first letters extracted.
+
+Of these strategies, the `loop` approach is the fastest, although `list-comprehension`, `map`,  and `reduce` have near-identical performance for the test data.
+All approaches are fairly succinct and readable, although the 'classic' loop is probably the easiest understood by those coming to Python from other programming languages.
+
+
+The least performant for the test data was using a `generator-expression`, `re.findall` and  `re.sub` (_least performant_).
+
+To compare performance of the approaches, take a look at the [Performance article][article-performance].
+
+[approach-functools-reduce]: https://exercism.org/tracks/python/exercises/acronym/approaches/functools-reduce
+[approach-generator-expression]: https://exercism.org/tracks/python/exercises/acronym/approaches/generator-expression
+[approach-list-comprehension]: https://exercism.org/tracks/python/exercises/acronym/approaches/list-comprehension
+[approach-loop]: https://exercism.org/tracks/python/exercises/acronym/approaches/loop
+[approach-map-function]: https://exercism.org/tracks/python/exercises/acronym/approaches/map-function
+[approach-regex-join]: https://exercism.org/tracks/python/exercises/acronym/approaches/regex-join
+[approach-regex-sub]: https://exercism.org/tracks/python/exercises/acronym/approaches/regex-sub
+[article-performance]: https://exercism.org/tracks/python/exercises/isogram/articles/performance

affine-cipher/affine_cipher.py

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+def encode(plain_text, a, b):
+    pass
+
+
+def decode(ciphered_text, a, b):
+    pass