week 273

9 files changed, 434 insertions, 0 deletions

diff --git a/challenge-273/iangoodnight/python/.gitignore b/challenge-273/iangoodnight/python/.gitignore
new file mode 100644
index 0000000000..c18dd8d83c
--- /dev/null
+++ b/challenge-273/iangoodnight/python/.gitignore
@@ -0,0 +1 @@
+__pycache__/
diff --git a/challenge-273/iangoodnight/python/README.md b/challenge-273/iangoodnight/python/README.md
new file mode 100644
index 0000000000..31ae6aed6e
--- /dev/null
+++ b/challenge-273/iangoodnight/python/README.md
@@ -0,0 +1,244 @@
+# Perl Weekly Challenge - 273
+
+Welcome to [Week #273][0] of [The Weekly Challenge][1].
+
+## Task 1: Percentage of Character
+
+**Submitted by:** [Mohammad Sajid Anwar][2]
+
+You are given a string, `$str` and a character `$char`.
+
+Write a script to return the percentage, nearest whole, of given character in
+the given string.
+
+**Example 1**
+
+```
+Input: $str = "perl", $char = "e"
+Output: 25
+```
+
+**Example 2**
+
+```
+Input: $str = "java", $char = "a"
+Output: 50
+```
+
+**Example 3**
+
+```
+Input: $str = "python", $char = "m"
+Output: 0
+```
+
+**Example 4**
+
+```
+Input: $str = "ada", $char = "a"
+Output: 67
+```
+
+**Example 5**
+
+```
+Input: $str = "ballerina", $char = "l"
+Output: 22
+```
+
+**Example 6**
+
+```
+Input: $str = "analitik", $char = "k"
+Output: 13
+```
+
+### Solution
+
+### Testing
+
+Our [solution][3] is intentionally designed to be simple and easy to understand.
+We have defined two constants, `PERCENTAGE_FACTOR` and `ROUNDING_THRESHOLD`, to
+help with the calculation of the percentage. The `percentage_of_character`
+function takes two arguments, `string` and `char`, and returns the percentage of
+the character in the string, rounded to the nearest whole number.  Using a
+declarative approach, we first calculate the length of the string and the number
+of times the character appears in the string. We then calculate the percentage
+of the character in the string as a decimal, convert it to a percentage, and
+round it to the nearest whole number using half up rounding.  It came as a
+surprise to find that python implements an `even up` rounding by default, which
+could lead to incorrect results. With an `even up` rounding strategy, a value of
+`0.5` would be rounded down to `0`, whereas we want it to be rounded up to `1`.
+The rounding method we have used is known as `half up` rounding, which rounds
+`0.5` up to `1`.  The function returns `0` if the string or character are empty.
+
+```python
+PERCENTAGE_FACTOR = 100   # multiply the decimal value by 100 to get percentage
+ROUNDING_THRESHOLD = 0.5  # ensure we are rounding half up, rather than even up
+
+
+def percentage_of_character(string: str, char: str) -> int:
+    """Return the percentage of given character in the given string.
+
+    Args:
+        string: The string to search for the character.
+        char: The character to search for in the string.
+
+    Returns:
+        The percentage of the character in the string, rounded to the nearest
+        whole number.
+    """
+    # Get the length of the string for testing and calculating the percentage
+    string_length = len(string)
+    # Return 0 if the string or character are empty
+    if string_length == 0 or len(char) == 0:
+        return 0
+    # Count the number of times the character appears in the string
+    char_count = string.count(char)
+    # Calculate the percentage of the character in the string as a decimal
+    decimal_percentage = char_count / string_length
+    # Convert the decimal percentage to a percentage
+    percentage = decimal_percentage * PERCENTAGE_FACTOR
+    # Round the percentage to the nearest whole number (half up rounding)
+    rounded_percentage = int(percentage + ROUNDING_THRESHOLD)
+
+    return rounded_percentage
+```
+
+### Testing
+
+We have written a comprehensive test suite to validate our solution. We have
+covered both the base and extra test cases to ensure our solution works as
+expected. Runnning the test suite requires the `pytest` module, which can be
+installed using `pip install pytest`.
+
+```python
+from challenge273.task1 import percentage_of_character
+
+
+def test_examples() -> None:
+    """Test if function returns correct percentage of character"""
+    assert percentage_of_character("perl", "e") == 25
+    assert percentage_of_character("java", "a") == 50
+    assert percentage_of_character("python", "m") == 0
+    assert percentage_of_character("ada", "a") == 67
+    assert percentage_of_character("ballerina", "l") == 22
+    assert percentage_of_character("analitik", "k") == 13
+
+
+def test_empty_string() -> None:
+    """Test if function returns 0 for empty string"""
+    assert percentage_of_character("", "a") == 0
+
+
+def test_empty_character() -> None:
+    """Test if function returns 0 for empty character"""
+    assert percentage_of_character("python", "") == 0
+```
+
+The test suite can be run using the following command:
+
+```bash
+$ pytest test_task1.py
+```
+
+## Task 2: B After A
+
+**Submitted by:** [Mohammad Sajid Anwar][2]
+
+You are given a string, `$str`.
+
+Write a script to return `true` if there is at least one `b`, and no `a` appears
+after the first `b`.
+
+**Example 1**
+
+```
+Input: $str = "aabb"
+Output: true
+```
+
+**Example 2**
+
+```
+Input: $str = "abab"
+Output: false
+```
+
+**Example 3**
+
+```
+Input: $str = "aaa"
+Output: false
+```
+
+**Example 4**
+
+```
+Input: $str = "bbb"
+Output: true
+```
+
+### Solution
+
+Our [solution][4] is simple and easy to understand. The `b_after_a` function
+takes a single argument, `string`, and returns `True` if there is at least one
+`b` in the string and no `a` appears after the first `b`.  We first check if
+there is no `b` in the string, in which case we return `False`. We then find the
+index of the first `b` in the string and slice the string after the first `b`.
+Finally, we check if there is no `a` in the slice and return `True` if that is
+the case; otherwise, we return `False`.
+
+```python
+def b_after_a(string: str) -> bool:
+    """
+    Returns `true` if there is at least one `b`, and no `a` appears after the
+    first `b`.
+
+    Args:
+        string: The input string to check for the presence of `b` and `a`.
+
+    Returns:
+        `True` if there is at least one `b`, and no `a` appears after the first
+        `b`; otherwise, `False`.
+    """
+    if "b" not in string:  # fails if there is no `b` in the string
+        return False
+    b_index = string.index("b")
+    # grab a slice of the string after the first `b`
+    sliced_after_b = string[b_index + 1:]
+    # check if there is no `a` in the slice
+    return "a" not in sliced_after_b
+```
+
+### Testing
+
+We have written a comprehensive test suite to validate our solution. We have
+covered both the base and extra test cases to ensure our solution works as
+expected. Runnning the test suite requires the `pytest` module, which can be
+installed using `pip install pytest`.
+
+```python
+from challenge273.task2 import b_after_a
+
+
+def test_examples() -> None:
+    """Test if function returns correct percentage of character"""
+    assert b_after_a("aabb") is True
+    assert b_after_a("abab") is False
+    assert b_after_a("aaa") is False
+    assert b_after_a("bbb") is True
+```
+
+The test suite can be run using the following command:
+
+```bash
+$ pytest test_task2.py
+```
+
+[0]: https://perlweeklychallenge.org/blog/perl-weekly-challenge-272/
+[1]: https://perlweeklychallenge.org
+[2]: https://manwar.org/
+[3]: ./task1.py
+[4]: ./task2.py
+
diff --git a/challenge-273/iangoodnight/python/__init__.py b/challenge-273/iangoodnight/python/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/challenge-273/iangoodnight/python/__init__.py
diff --git a/challenge-273/iangoodnight/python/requirements.txt b/challenge-273/iangoodnight/python/requirements.txt
new file mode 100644
index 0000000000..4631673210
--- /dev/null
+++ b/challenge-273/iangoodnight/python/requirements.txt
@@ -0,0 +1,4 @@
+iniconfig==2.0.0
+packaging==24.1
+pluggy==1.5.0
+pytest==8.2.2
diff --git a/challenge-273/iangoodnight/python/task1.py b/challenge-273/iangoodnight/python/task1.py
new file mode 100644
index 0000000000..47f77081f6
--- /dev/null
+++ b/challenge-273/iangoodnight/python/task1.py
@@ -0,0 +1,85 @@
+"""
+## Task 1: Percentage of Character
+
+**Submitted by:** [Mohammad Sajid Anwar][0]
+
+You are given a string, `$str` and a character `$char`.
+
+Write a script to return the percentage, nearest whole, of given character in
+the given string.
+
+**Example 1**
+
+```
+Input: $str = "perl", $char = "e"
+Output: 25
+```
+
+**Example 2**
+
+```
+Input: $str = "java", $char = "a"
+Output: 50
+```
+
+**Example 3**
+
+```
+Input: $str = "python", $char = "m"
+Output: 0
+```
+
+**Example 4**
+
+```
+Input: $str = "ada", $char = "a"
+Output: 67
+```
+
+**Example 5**
+
+```
+Input: $str = "ballerina", $char = "l"
+Output: 22
+```
+
+**Example 6**
+
+```
+Input: $str = "analitik", $char = "k"
+Output: 13
+```
+
+[0]: https://manwar.org/
+"""
+
+PERCENTAGE_FACTOR = 100   # multiply the decimal value by 100 to get percentage
+ROUNDING_THRESHOLD = 0.5  # ensure we are rounding half up, rather than even up
+
+
+def percentage_of_character(string: str, char: str) -> int:
+    """Return the percentage of given character in the given string.
+
+    Args:
+        string: The string to search for the character.
+        char: The character to search for in the string.
+
+    Returns:
+        The percentage of the character in the string, rounded to the nearest
+        whole number.
+    """
+    # Get the length of the string for testing and calculating the percentage
+    string_length = len(string)
+    # Return 0 if the string or character are empty
+    if string_length == 0 or len(char) == 0:
+        return 0
+    # Count the number of times the character appears in the string
+    char_count = string.count(char)
+    # Calculate the percentage of the character in the string as a decimal
+    decimal_percentage = char_count / string_length
+    # Convert the decimal percentage to a percentage
+    percentage = decimal_percentage * PERCENTAGE_FACTOR
+    # Round the percentage to the nearest whole number (half up rounding)
+    rounded_percentage = int(percentage + ROUNDING_THRESHOLD)
+
+    return rounded_percentage
diff --git a/challenge-273/iangoodnight/python/task2.py b/challenge-273/iangoodnight/python/task2.py
new file mode 100644
index 0000000000..bda082bb9e
--- /dev/null
+++ b/challenge-273/iangoodnight/python/task2.py
@@ -0,0 +1,61 @@
+"""
+## Task 2: B After A
+
+**Submitted by:** [Mohammad Sajid Anwar][0]
+
+You are given a string, `$str`.
+
+Write a script to return `true` if there is at least one `b`, and no `a`
+appears after the first `b`.
+
+**Example 1**
+
+```
+Input: $str = "aabb"
+Output: true
+```
+
+**Example 2**
+
+```
+Input: $str = "abab"
+Output: false
+```
+
+**Example 3**
+
+```
+Input: $str = "aaa"
+Output: false
+```
+
+**Example 4**
+
+```
+Input: $str = "bbb"
+Output: true
+```
+
+[0]: https://manwar.org/
+"""
+
+
+def b_after_a(string: str) -> bool:
+    """
+    Returns `true` if there is at least one `b`, and no `a` appears after the
+    first `b`.
+
+    Args:
+        string: The input string to check for the presence of `b` and `a`.
+
+    Returns:
+        `True` if there is at least one `b`, and no `a` appears after the first
+        `b`; otherwise, `False`.
+    """
+    if "b" not in string:  # fails if there is no `b` in the string
+        return False
+    b_index = string.index("b")
+    # grab a slice of the string after the first `b`
+    sliced_after_b = string[b_index + 1:]
+    # check if there is no `a` in the slice
+    return "a" not in sliced_after_b
diff --git a/challenge-273/iangoodnight/python/tests/__init__.py b/challenge-273/iangoodnight/python/tests/__init__.py
new file mode 100644
index 0000000000..c06655e4a4
--- /dev/null
+++ b/challenge-273/iangoodnight/python/tests/__init__.py
@@ -0,0 +1,7 @@
+"""
+Adds the parent directory to the path so that the modules can be imported from
+our tests.
+"""
+import sys
+
+sys.path.append("..")
diff --git a/challenge-273/iangoodnight/python/tests/test_task1.py b/challenge-273/iangoodnight/python/tests/test_task1.py
new file mode 100644
index 0000000000..b27365fdac
--- /dev/null
+++ b/challenge-273/iangoodnight/python/tests/test_task1.py
@@ -0,0 +1,22 @@
+"""Tests for task1.py"""
+from python.task1 import percentage_of_character
+
+
+def test_examples() -> None:
+    """Test if function returns correct percentage of character"""
+    assert percentage_of_character("perl", "e") == 25
+    assert percentage_of_character("java", "a") == 50
+    assert percentage_of_character("python", "m") == 0
+    assert percentage_of_character("ada", "a") == 67
+    assert percentage_of_character("ballerina", "l") == 22
+    assert percentage_of_character("analitik", "k") == 13
+
+
+def test_empty_string() -> None:
+    """Test if function returns 0 for empty string"""
+    assert percentage_of_character("", "a") == 0
+
+
+def test_empty_character() -> None:
+    """Test if function returns 0 for empty character"""
+    assert percentage_of_character("python", "") == 0
diff --git a/challenge-273/iangoodnight/python/tests/test_task2.py b/challenge-273/iangoodnight/python/tests/test_task2.py
new file mode 100644
index 0000000000..12dee45e22
--- /dev/null
+++ b/challenge-273/iangoodnight/python/tests/test_task2.py
@@ -0,0 +1,10 @@
+"""Tests for task2.py"""
+from python.task2 import b_after_a
+
+
+def test_examples() -> None:
+    """Test if function returns correct percentage of character"""
+    assert b_after_a("aabb") is True
+    assert b_after_a("abab") is False
+    assert b_after_a("aaa") is False
+    assert b_after_a("bbb") is True