Add Microsoft Excel Column Title to Column Number Conversion (#4849)

* Added excel column title to number algorithm as part of conversions

* Renamed file to better reflect algorithm function

* Removed duplicate file

* Update excel_title_to_column.py

* Update excel_title_to_column.py

Co-authored-by: John Law <johnlaw.po@gmail.com>

conversions/excel_title_to_column.py

@@ -0,0 +1,33 @@
+def excel_title_to_column(column_title: str) -> int:
+    """
+    Given a string column_title that represents
+    the column title in an Excel sheet, return
+    its corresponding column number.
+
+    >>> excel_title_to_column("A")
+    1
+    >>> excel_title_to_column("B")
+    2
+    >>> excel_title_to_column("AB")
+    28
+    >>> excel_title_to_column("Z")
+    26
+    """
+    assert column_title.isupper()
+    answer = 0
+    index = len(column_title) - 1
+    power = 0
+
+    while index >= 0:
+        value = (ord(column_title[index]) - 64) * pow(26, power)
+        answer += value
+        power += 1
+        index -= 1
+
+    return answer
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()