Development (#23)

* add ceil

* add floor

* get first digit of a number

* sum to n using formula

* Formatted with psf/black

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

Author: realDuYuanChao

maths/ceil.py

@@ -0,0 +1,14 @@
+def ceil(number) -> int:
+    """
+    >>> import math
+    >>> numbers = [-3.14, 3.14, -3, 3, 0, 0.0, -0.0, -1234.567, 1234.567]
+    >>> all(math.ceil(num) == ceil(num) for num in numbers)
+    True
+    """
+    return int(number) if number - int(number) <= 0 else int(number) + 1
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()

maths/first_digit.py

@@ -0,0 +1,21 @@
+def first_digit(number: int) -> int:
+    """
+    >>> first_digit(-123)
+    1
+    >>> first_digit(0)
+    0
+    >>> first_digit(123)
+    1
+    >>> first_digit(123456789)
+    1
+    """
+    number = abs(number)
+    while number >= 10:
+        number //= 10
+    return number
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()

maths/first_digit_by_str.py

@@ -0,0 +1,18 @@
+def first_digit(number: int) -> int:
+    """
+    >>> first_digit(-123)
+    1
+    >>> first_digit(0)
+    0
+    >>> first_digit(123)
+    1
+    >>> first_digit(123456789)
+    1
+    """
+    return int(str(abs(number))[0])
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()

maths/first_digit_recursion.py

@@ -0,0 +1,19 @@
+def first_digit_recursion(number: int) -> int:
+    """
+    >>> first_digit_recursion(-123)
+    1
+    >>> first_digit_recursion(0)
+    0
+    >>> first_digit_recursion(123)
+    1
+    >>> first_digit_recursion(123456789)
+    1
+    """
+    number = abs(number)
+    return number if number < 10 else first_digit_recursion(number // 10)
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()

maths/floor.py

@@ -0,0 +1,14 @@
+def floor(number) -> int:
+    """
+    >>> numbers = [-3.14, 3.14, -3, 3, 0, 0.0, -0.0, -1234.567, 1234.567]
+    >>> import math
+    >>> all(math.floor(num) == floor(num) for num in numbers)
+    True
+    """
+    return int(number) if number - int(number) >= 0 else int(number) - 1
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()

maths/sum_to_n_formula.py

@@ -0,0 +1,20 @@
+def sum_to_n(n: int) -> int:
+    """
+    >>> sum_to_n(0)
+    0
+    >>> sum_to_n(1)
+    1
+    >>> sum_to_n(2)
+    3
+    >>> sum_to_n(10)
+    55
+    >>> sum_to_n(100)
+    5050
+    """
+    return (1 + n) * n // 2
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()