Merge pull request #176 from ikostan/exercism-sync/d62a8d8fd012d080

[Sync Iteration] python/wordy/2

Author: ikostan

solutions/python/wordy/2/wordy.py

@@ -0,0 +1,118 @@
+"""
+Parse and evaluate simple math word problems
+returning the answer as an integer.
+
+Handle a set of operations, in sequence.
+
+Since these are verbal word problems, evaluate
+the expression from left-to-right, ignoring the
+typical order of operations.
+"""
+
+import string
+
+STR_TO_OPERATOR: dict = {
+    "plus": "+",
+    "minus": "-",
+    "multiplied": "*",
+    "divided": "/",
+}
+
+WRONG_OPERATORS: list[str] = [
+    "plus?",
+    "minus?",
+    "multiplied?",
+    "divided?",
+    "plus plus",
+    "plus multiplied",
+    "minus multiplied",
+    "minus minus",
+    "multiplied multiplied",
+    "divided divided",
+    "What is?",
+]
+
+
+def answer(question: str) -> int:
+    _validate_errors(question)
+    result: int = 0
+    new_question: list[str] = _reformat(question)
+
+    if len(new_question) <= 3:
+        try:
+            _validate_evaluation_pattern(new_question)
+            eval_str: str = "".join(new_question)
+            result = eval(eval_str)
+            return result
+        except Exception:
+            raise ValueError("syntax error")
+
+    while len(new_question) >= 3:
+        try:
+            _validate_evaluation_pattern(new_question[:3])
+            eval_str: str = "".join(new_question[:3])
+            val: int = eval(eval_str)
+            result = val
+            new_question = [str(result)] + new_question[3:]
+            if len(new_question) < 3:
+                _validate_evaluation_pattern(new_question)
+                return eval("".join(new_question))
+        except Exception:
+            raise ValueError("syntax error")
+    return result
+
+
+def _validate_evaluation_pattern(val: list) -> None:
+    if len(val) == 3 and not val[1] in STR_TO_OPERATOR.values():
+        raise ValueError("syntax error")
+
+    if len(val) == 2 and not val[0] in STR_TO_OPERATOR.values():
+        raise ValueError("syntax error")
+
+
+def _reformat(question: str) -> list:
+    # 1: Remove '?' mark
+    question = question.replace("?", "")
+    # 2: Convert all operators writen in word into proper math sign
+    question_list: list[str] = question.split()
+    formated_question_list: list[str] = []
+    for i, item in enumerate(question_list):
+        if not (
+            item.isdigit()
+            or item in STR_TO_OPERATOR.keys()
+            or item in STR_TO_OPERATOR.values()
+            or any(val in item for val in STR_TO_OPERATOR.values())
+        ):
+            continue
+        elif item in STR_TO_OPERATOR.keys():
+            formated_question_list.append(STR_TO_OPERATOR[item])
+        elif item.isdigit():
+            formated_question_list.append(item)
+        elif item in STR_TO_OPERATOR.values():
+            formated_question_list.append(item)
+        elif any(val in item for val in STR_TO_OPERATOR.values()):
+            formated_question_list.append(item)
+
+    return formated_question_list
+
+
+def _validate_errors(question: str) -> None:
+    if "cubed" in question:
+        raise ValueError("unknown operation")
+
+    for item in WRONG_OPERATORS:
+        if item in question:
+            raise ValueError("syntax error")
+
+    digits: list[bool] = []
+    for char in question:
+        if char.isdigit():
+            digits.append(True)
+
+    operators: list[bool] = []
+    for key, val in STR_TO_OPERATOR.items():
+        if key in question or val in question:
+            operators.append(True)
+
+    if not any(digits + operators):
+        raise ValueError("unknown operation")