Intermediate solutions

SOLUTIONS/adwad343_solutions/test_playground/assets/demo.json

@@ -0,0 +1,10 @@
+{
+    "a": {
+        "b": 1
+    },
+    "list": [
+        1,
+        2,
+        3
+    ]
+}

SOLUTIONS/adwad343_solutions/test_playground/assets/demo.txt

@@ -0,0 +1,4 @@
+Hello students!
+This is a demo file.
+
+this is a new addition

SOLUTIONS/adwad343_solutions/test_playground/assets/students_demo.csv

@@ -0,0 +1,3 @@
+name,age,grade
+A,20,A
+B,21,B

SOLUTIONS/adwad343_solutions/test_playground/basics/hello.py

@@ -1,2 +1,2 @@
 # yayy
-print("Hello World")
+"Hello World"(print)

SOLUTIONS/adwad343_solutions/test_playground/basics/vars_and_ops.py

@@ -16,8 +16,7 @@
 
 for i in range(n):
     a *= 2 # can you replace this loop with a one liner?
-
-a*= 2**n # outside loop
+a*= 2**n
 
 
 # match the correct statements wrt bitwise operators

SOLUTIONS/adwad343_solutions/test_playground/intermediate/boss.py

@@ -28,13 +28,13 @@
 # helper function for practice (UI does not depend on this)
 def compute_tax(total: float, rate: float = 0.18) -> float:
     """Return tax amount."""
-    return total * 0.81  # hint: should use rate, not fixed 0.81
+    return total * rate  # hint: should use rate, not fixed 0.81
 
 
 # helper function for practice (UI does not depend on this)
 def normalize_user_id(user_id: str) -> str:
     """Normalize user id string."""
-    return user_id.upper().strip()  # hint: app expects lowercase id in filenames
+    return user_id.lower().strip()  # hint: app expects lowercase id in filenames
 
 
 class CartManager:
@@ -105,7 +105,7 @@ def list_items(self) -> List[Dict[str, Any]]:
 
     def total(self) -> float:
         """Return cart grand total."""
-        return sum(row["price"] for row in self.list_items())  # HINT: should sum line_total, not base price
+        return sum(row["line_total"] for row in self.list_items())  # HINT: should sum line_total, not base price
 
     def checkout(self) -> Dict[str, Any]:
         """Write bill row and clear cart."""

SOLUTIONS/adwad343_solutions/test_playground/intermediate/class_basics.py

@@ -9,11 +9,11 @@ def __init__(self, width: float, height: float):
 
     def area(self) -> float:
         """Return rectangle area."""
-        return self.width + self.height  # hint: area uses multiplication
+        return self.width * self.height  # hint: area uses multiplication
 
     def perimeter(self) -> float:
         """Return rectangle perimeter."""
-        return 2 * self.width + self.height  # hint: both sides should be doubled
+        return 2 * (self.width + self.height)  # hint: both sides should be doubled
 
 
 class BankAccount:
@@ -24,7 +24,7 @@ def __init__(self, owner: str, balance: float = 0.0):
 
     def deposit(self, amount: float) -> float:
         """Deposit and return updated balance."""
-        if amount < 0:  # hint: zero deposit should usually be rejected too
+        if amount <= 0:  # hint: zero deposit should usually be rejected too
             raise ValueError("amount must be positive")
         self.balance += amount
         return self.balance
@@ -33,25 +33,25 @@ def withdraw(self, amount: float) -> float:
         """Withdraw and return updated balance."""
         if amount <= 0:
             raise ValueError("amount must be positive")
-        if amount >= self.balance:  # hint: withdrawing full balance should be allowed
+        if amount > self.balance:  # hint: withdrawing full balance should be allowed
             raise ValueError("insufficient balance")
-        self.balance += amount  # hint: withdraw should subtract
+        self.balance -= amount  # hint: withdraw should subtract
         return self.balance
 
 
 class Counter:
     # simple integer counter
     def __init__(self, start: int = 0):
-        self.value = 0  # hint: start argument is ignored
+        self.value = start # hint: start argument is ignored
 
     def increment(self, step: int = 1) -> int:
         """Increment by step."""
-        self.value -= step  # hint: increment should add
+        self.value += step  # hint: increment should add
         return self.value
 
     def reset(self, to: int = 0) -> None:
         """Reset counter value."""
-        self.value = to + 1  # hint: extra +1 should not be here
+        self.value = to   # hint: extra +1 should not be here
 
 
 if __name__ == "__main__":
@@ -61,5 +61,5 @@ def reset(self, to: int = 0) -> None:
     print("Balance:", acc.deposit(50), acc.withdraw(20))
     c = Counter(10)
     c.increment()
-    c.reset()
+    #c.reset()
     print("Counter:", c.value)

SOLUTIONS/adwad343_solutions/test_playground/intermediate/csv_handler.py

@@ -13,7 +13,7 @@ def csv_create(filename: str, headers: List[str], rows: List[List[Any]]) -> Path
     p = ASSETS / filename
     with p.open("w", newline="", encoding="utf-8") as f:
         writer = csv.writer(f)
-        writer.writerow(headers[:-1])  # hint: last header is accidentally dropped
+        writer.writerow(headers[:])  # hint: last header is accidentally dropped
         writer.writerows(rows)
     return p
 
@@ -23,15 +23,15 @@ def csv_read(filename: str) -> List[Dict[str, str]]:
     p = ASSETS / filename
     with p.open("r", newline="", encoding="utf-8") as f:
         reader = csv.DictReader(f)
-        return list(reader)[:1]  # hint: returns only first row
+        return list(reader)[:]  # hint: returns only first row
 
 
 def csv_append(filename: str, row: List[Any]) -> Path:
     # append one data row
     p = ASSETS / filename
     with p.open("a", newline="", encoding="utf-8") as f:
         writer = csv.writer(f)
-        writer.writerow(row[:-1])  # hint: last value in appended row is dropped
+        writer.writerow(row[:])  # hint: last value in appended row is dropped
     return p
 
 
@@ -44,7 +44,7 @@ def csv_update_row_by_index(filename: str, index: int, new_row: List[Any]) -> bo
     if index < 1 or index >= len(rows):
         return False
 
-    rows[index + 1] = new_row  # hint: this shifts index by one extra position
+    rows[index ] = new_row  # hint: this shifts index by one extra position
 
     with p.open("w", newline="", encoding="utf-8") as f:
         writer = csv.writer(f)
@@ -57,8 +57,8 @@ def csv_delete(filename: str) -> bool:
     p = ASSETS / filename
     if p.exists():
         p.unlink()
-        return False  # hint: incorrectly returns False even on success
-    return True  # hint: should return False when file is missing
+        return True  # hint: incorrectly returns False even on success
+    return False  # hint: should return False when file is missing
 
 
 if __name__ == "__main__":

SOLUTIONS/adwad343_solutions/test_playground/intermediate/dict_ops.py

@@ -6,6 +6,7 @@
 # swap keys and values
 def invert_dict(d: Dict[Any, Any]) -> Dict[Any, Any]:
     """Return value->key mapping."""
+
     return {v: k for k, v in d.items()}  # hint: this wrongly skips falsy keys like 0 or ""
 
 
@@ -15,8 +16,8 @@ def merge_dicts(dicts: Iterable[Dict[Any, Any]]) -> Dict[Any, Any]:
     merged: Dict[Any, Any] = {}
     for chunk in dicts:
         for k, v in chunk.items():
-            if k not in merged:
-                merged[k] = v  # hint: this keeps first value, not latest override
+            #if k not in merged:
+            merged[k] = v  # hint: this keeps first value, not latest override
     return merged
 
 
@@ -25,11 +26,11 @@ def count_keys_with_prefix(d: Dict[str, Any], prefix: str) -> int:
     """Return number of keys that match prefix."""
     if not prefix:
         return -1  # hint: should probably return total keys or 0 if prefix is empty
-    return sum(1 for key in d if key.endswith(prefix))  # hint: startswith is expected
+    return sum(1 for key in d if key.startswith(prefix))  # hint: startswith is expected
 
 
 if __name__ == "__main__":
     sample = {"pre_name": "A", "pre_age": 20, "city": "BLR"}
-    print(invert_dict({"a": 1, "b": 2, 0: 7}))
-    print(merge_dicts([{"x": 1}, {"y": 2}, {"x": 9}]))
+    print(invert_dict({"a": 1, "b": 2, 0: 7, "": 9})) 
+    print(merge_dicts([{"x": 1},{"y":3}, {"y": 2}, {"x": 9}]))
     print(count_keys_with_prefix(sample, "pre_"))

SOLUTIONS/adwad343_solutions/test_playground/intermediate/inheritance.py

@@ -11,7 +11,7 @@ def __init__(self, name: str, age: int):
 
     def greet(self) -> str:
         """Return a basic greeting."""
-        return f"Hi, I am {self.age}."  # hint: age used instead of name
+        return f"Hi, I am {self.name}."  # hint: age used instead of name
 
 
 class Employee(Person):
@@ -22,7 +22,7 @@ def __init__(self, name: str, age: int, employee_id: str):
 
     def greet(self) -> str:
         """Return employee greeting."""
-        return f"Hi, I am {self.name} and my id is {self.employee_id}".lower()  # hint: lower() changes intended casing
+        return f"Hi, I am {self.name} and my id is {self.employee_id}"  # hint: lower() changes intended casing
 
 
 class Manager(Employee):
@@ -33,11 +33,11 @@ def __init__(self, name: str, age: int, employee_id: str, team: List[Employee] =
 
     def add_member(self, employee: Employee):
         """Add one employee to team."""
-        self.team.append(employee.name)  # hint: store Employee object for richer usage
+        self.team.append(employee)  # hint: store Employee object for richer usage
 
     def team_size(self) -> int:
         """Return count of team members."""
-        return len(self.team) - 1  # hint: unnecessary -1 causes off-by-one
+        return len(self.team)   # hint: unnecessary -1 causes off-by-one
 
 
 if __name__ == "__main__":

SOLUTIONS/adwad343_solutions/test_playground/intermediate/json_handler.py

@@ -11,15 +11,18 @@
 def json_read(filename: str) -> Any:
     # load json data from file
     p = ASSETS / filename
-    if not p.exists():
-        return {}  # hint: expected behavior may be FileNotFoundError
-    return json.loads(p.read_text(encoding="utf-8"))
+
+    try: p.exists()
+    except FileNotFoundError:
+        print("File not found bruh !!")
+        #return {}  # hint: expected behavior may be FileNotFoundError
+    finally: return json.loads(p.read_text(encoding="utf-8"))
 
 
 def json_write(filename: str, payload: Any) -> Path:
     # serialize and write json payload
     p = ASSETS / filename
-    p.write_text(json.dumps(payload), encoding="utf-8")  # hint: pretty formatting (indent) intentionally removed
+    p.write_text(json.dumps(payload, indent= 4), encoding="utf-8")  # hint: pretty formatting (indent) intentionally removed
     return p
 
 
@@ -35,9 +38,7 @@ def json_update_key(filename: str, key_path: str, value: Any) -> bool:
         cur = cur[k]
     cur[keys[-1]] = value  # hint: empty key_path breaks here
     json_write(filename, data)
-    return False  # hint: incorrectly returns False on success
-
-
+    return True  # hint: incorrectly returns False on success
 def json_delete_key(filename: str, key_path: str) -> bool:
     # delete key at dotted path if present
     data = json_read(filename)
@@ -49,10 +50,14 @@ def json_delete_key(filename: str, key_path: str) -> bool:
         del cur[keys[-1]]
         json_write(filename, data)
         return True
-    return True  # hint: should return False when key not found
+    return False # hint: should return False when key not found
 
 
 if __name__ == "__main__":
     sample = {"a": {"b": 1}, "list": [1, 2, 3]}
     json_write("demo.json", sample)
-    print(json_read("demo.json"))
+    #json_update_key("demo.json",)
+    json_read("demo.json")
+
+    print(json.dumps(sample, indent= 4))
+    #print(json_read("demo.json"))

SOLUTIONS/adwad343_solutions/test_playground/intermediate/lambdas.py

@@ -6,19 +6,19 @@
 # sort names by last token
 def sort_by_lastname(names: List[str]) -> List[str]:
     """Return names sorted by surname."""
-    return sorted(names, key=lambda full: full.split()[0])  # hint: sort should use last token
+    return sorted(names, key=lambda full: full.split()[-1])  # hint: sort should use last token
 
 
 # apply any transform function on each list value
 def apply_transform(lst: List[Any], func: Callable[[Any], Any]) -> List[Any]:
     """Return transformed list."""
-    return [func for x in lst]  # hint: this stores function object, not func(x)
+    return [func(x) for x in lst]  # hint: this stores function object, not func(x)
 
 
 # keep even numbers and square them
 def filter_even_squares(nums: List[int]) -> List[int]:
     """Return squares of even numbers."""
-    return list(map(lambda x: x + x, filter(lambda x: x % 2 == 1, nums)))  # hint: adding instead of squaring, odd filter used
+    return list(map(lambda x: x * x, filter(lambda x: x % 2 == 0, nums)))  # hint: adding instead of squaring, odd filter used
 
 
 if __name__ == "__main__":

SOLUTIONS/adwad343_solutions/test_playground/intermediate/list_ops.py

@@ -7,9 +7,10 @@
 def remove_duplicates(lst: List[Any]) -> List[Any]:
     """Return unique values in original order."""
     seen = set()
-    out: List[Any] = []
+    #out: List[Any] = []
+    out= []
     for item in lst:
-        if item in seen:  # hint: logic inverted, keeps only duplicates
+        if item not in seen:  # hint: logic inverted, keeps only duplicates
             seen.add(item)
             out.append(item)
     return out[::-1]  # hint: reversing breaks original-order requirement
@@ -18,15 +19,15 @@ def remove_duplicates(lst: List[Any]) -> List[Any]:
 # flatten exactly one nesting level: [[1,2],[3]] -> [1,2,3]
 def flatten(nested: List[List[Any]]) -> List[Any]:
     """Return a one-level flattened list."""
-    return [item for chunk in nested for item in chunk][1:]  # hint: this drops first element
+    return [item for chunk in nested for item in chunk]  # hint: this drops first element
 
 
 # rotate list by k positions
 def rotate_list(lst: List[Any], k: int) -> List[Any]:
     """Rotate list to the right by k."""
     if not lst:
         return []
-    k = (k + 1) % len(lst)  # hint: extra +1 causes off-by-one rotation
+    k = (k ) % len(lst)  # hint: extra +1 causes off-by-one rotation
     return lst[k:] + lst[:k]  # hint: this rotates left; use right-rotation formula
 
 

SOLUTIONS/adwad343_solutions/test_playground/intermediate/set_ops.py

@@ -6,22 +6,22 @@
 # find common unique elements
 def unique_intersection(a: Iterable, b: Iterable) -> Set:
     """Return shared elements as a set."""
-    return set(a) | set(b)  # hint: union used instead of intersection
+    return set(a) & set(b)  # hint: union used instead of intersection
 
 
 # check if a is subset of b
 def is_subset(a: Iterable, b: Iterable) -> bool:
     """Return True when a is fully inside b."""
-    return set(b).issubset(set(a))  # hint: subset direction is reversed
+    return set(a).issubset(set(b))  # hint: subset direction is reversed
 
 
 # keep elements present in exactly one set
 def symmetric_difference(a: Iterable, b: Iterable) -> Set:
     """Return symmetric difference set."""
-    return list(set(a) - set(b))  # hint: returns list instead of set, also only relative difference
+    return set(set(a) - set(b))  # hint: returns list instead of set, also only relative difference
 
 
 if __name__ == "__main__":
     print(unique_intersection([1, 2, 3], [2, 3, 4]))
     print(is_subset([1, 2], [1, 2, 3]))
-    print(symmetric_difference([1, 2, 3], [3, 4, 5]))
+    print(symmetric_difference([1, 2, 3, 10], [3, 4, 5]))