src/cpl_query/base/queryable_abc.py

@@ -5,7 +5,7 @@ from typing import Optional, Callable, Union
 class QueryableABC(ABC):
 
     @abstractmethod
-    def all(self, _func: Callable) -> bool:
+    def all(self, _func: Callable = None) -> bool:
         r"""Checks if every element of list equals result found by function
 
         Parameter
@@ -20,7 +20,7 @@ class QueryableABC(ABC):
         pass
 
     @abstractmethod
-    def any(self, _func: Callable) -> bool:
+    def any(self, _func: Callable = None) -> bool:
         r"""Checks if list contains result found by function
 
         Parameter
@@ -35,7 +35,7 @@ class QueryableABC(ABC):
         pass
 
     @abstractmethod
-    def average(self, _func: Callable) -> Union[int, float, complex]:
+    def average(self, _func: Callable = None) -> Union[int, float, complex]:
         r"""Returns average value of list
 
         Parameter
@@ -145,7 +145,7 @@ class QueryableABC(ABC):
         pass
 
     @abstractmethod
-    def for_each(self, _func: Callable):
+    def for_each(self, _func: Callable = None):
         r"""Runs given function for each element of list
 
         Parameter
@@ -174,8 +174,9 @@ class QueryableABC(ABC):
             Last element of list: Optional[any]
         """
         pass
+
     @abstractmethod
-    def max(self, _func: Callable) -> Union[int, float, complex]:
+    def max(self, _func: Callable = None) -> Union[int, float, complex]:
         r"""Returns the highest value
 
         Parameter
@@ -199,9 +200,8 @@ class QueryableABC(ABC):
         """
         pass
 
-
     @abstractmethod
-    def min(self, _func: Callable) -> Union[int, float, complex]:
+    def min(self, _func: Callable = None) -> Union[int, float, complex]:
         r"""Returns the lowest value
 
         Parameter
@@ -216,7 +216,7 @@ class QueryableABC(ABC):
         pass
 
     @abstractmethod
-    def order_by(self, _func: Callable) -> 'QueryableABC':
+    def order_by(self, _func: Callable = None) -> 'QueryableABC':
         r"""Sorts elements by function in ascending order
 
         Parameter
@@ -231,7 +231,7 @@ class QueryableABC(ABC):
         pass
 
     @abstractmethod
-    def order_by_descending(self, _func: Callable) -> 'QueryableABC':
+    def order_by_descending(self, _func: Callable = None) -> 'QueryableABC':
         r"""Sorts elements by function in descending order
 
         Parameter
@@ -331,7 +331,7 @@ class QueryableABC(ABC):
         pass
 
     @abstractmethod
-    def sum(self, _func: Callable) -> Union[int, float, complex]:
+    def sum(self, _func: Callable = None) -> Union[int, float, complex]:
         r"""Sum of all values
 
         Parameter
@@ -376,7 +376,7 @@ class QueryableABC(ABC):
         pass
 
     @abstractmethod
-    def where(self, _func: Callable) -> 'QueryableABC':
+    def where(self, _func: Callable = None) -> 'QueryableABC':
         r"""Select element by function
 
         Parameter

src/cpl_query/base/sequence_abc.py

@@ -37,9 +37,6 @@ class SequenceABC(ABC):
     def type(self) -> type:
         return self._type
 
-    def reset(self):
-        self._values.reset()
-
     def to_list(self) -> list:
         r"""Converts :class: `cpl_query.base.sequence_abc.SequenceABC` to :class: `list`
 

src/cpl_query/base/sequence_values.py

@@ -19,20 +19,22 @@ class SequenceValues:
         if data is None:
             data = []
 
+        if len(data) > 0:
+            def type_check(_t: type, _l: list):
+                return all(isinstance(x, _t) for x in _l)
+
+            if not type_check(_t, data):
+                raise Exception(f'Unexpected type\nExpected type: {_t}')
+
         if not hasattr(data, '__iter__'):
             raise TypeError(f'{type(self).__name__} must be instantiated with an iterable object')
 
-        self._data = []
+        self._data = data
-        for element in data:
-            if _t is not None and type(element) != _t and not isinstance(type(element), _t) and not issubclass(type(element), _t):
-                raise Exception(f'Unexpected type: {type(element)}\nExpected type: {_t}')
-            self._data.append(element)
         self._index = 0
-        self._len = sum(1 for item in self._data)
         self._cycle = itertools.cycle(self._data)
 
     def __len__(self):
-        return self._len
+        return sum(1 for item in self._data)
 
     def __iter__(self):
         i = 0

src/cpl_query/enumerable/enumerable.py

@@ -1,7 +1,6 @@
-from typing import Union, Callable, Optional, Iterable
+from typing import Union, Callable, Optional
 
 from cpl_query._helper import is_number
-from cpl_query.base.sequence_values import SequenceValues
 from cpl_query.enumerable.enumerable_abc import EnumerableABC
 from cpl_query.enumerable.ordered_enumerable_abc import OrderedEnumerableABC
 from cpl_query.exceptions import ArgumentNoneException, ExceptionArgument, InvalidTypeException, IndexOutOfRangeException
@@ -88,7 +87,7 @@ class Enumerable(EnumerableABC):
         return result
 
     def element_at(self, _index: int) -> any:
-        self.reset()
+        self._values.reset()
         while _index >= 0:
             current = self.next()
             if _index == 0:
@@ -195,7 +194,7 @@ class Enumerable(EnumerableABC):
 
     @staticmethod
     def range(start: int, length: int) -> 'EnumerableABC':
-        return Enumerable(int, range(start, start + length, 1))
+        return Enumerable(int, range(start, length))
 
     def reverse(self: EnumerableABC) -> EnumerableABC:
         if self is None:
@@ -295,7 +294,6 @@ class Enumerable(EnumerableABC):
             raise ArgumentNoneException(ExceptionArgument.index)
 
         _list = self.to_list()
-
         index = len(_list) - _index
 
         if index >= len(_list) or index < 0:
@@ -322,12 +320,4 @@ class Enumerable(EnumerableABC):
         if _func is None:
             raise ArgumentNoneException(ExceptionArgument.func)
 
-        if _func is None:
+        return Enumerable(self.type, [x for x in self if _func(x)])
-            _func = _default_lambda
-
-        result = Enumerable(self.type)
-        for element in self:
-            if _func(element):
-                result.add(element)
-
-        return result

src/cpl_query/iterable/iterable_abc.py

@@ -15,21 +15,21 @@ class IterableABC(SequenceABC, QueryableABC):
         SequenceABC.__init__(self, t, values)
 
     def __getitem__(self, n) -> object:
-        r"""Gets item in enumerable at specified zero-based index
+        return self.to_list().__getitem__(n)
 
-        Parameter
+    def __delitem__(self, i: int):
-        --------
+        """Delete an item"""
-            n: the index of the item to get
+        _l = self.to_list()
+        del _l[i]
+        self._values = SequenceValues(_l, self._type)
 
-        Returns
+    def __setitem__(self, i: int, value):
-        -------
+        _l = self.to_list()
-            The element at the specified index.
+        _l.__setitem__(i, value)
+        self._values = SequenceValues(_l, self._type)
 
-        Raises
+    def __str__(self):
-        ------
+        return str(self.to_list())
-            IndexError if n > number of elements in the iterable
-        """
-        return list.__getitem__(self.to_list(), n)
 
     def append(self, __object: object) -> None:
         r"""Adds element to list

unittests/unittests_query/iterable_test_case.py

@@ -19,3 +19,17 @@ class IterableTestCase(unittest.TestCase):
 
         self.assertEqual(self._list.to_list(), [1, 2, 3])
         self.assertRaises(Exception, lambda v: self._list.append(v), '3')
+
+    def test_assign(self):
+        self._list.append(1)
+        self._list.append(2)
+        self._list.append(3)
+        self._list[0] = 42
+        self.assertEqual(self._list[0], 42)
+        self._list[0] = 1
+        self._list.append(42)
+        self.assertEqual(self._list[3], 42)
+        del self._list[3]
+
+        self.assertEqual(self._list.to_list(), [1, 2, 3])
+        self.assertRaises(Exception, lambda v: self._list.append(v), '3')