add repeat()

Author: cleoold

tests/test_usage.py

@@ -841,6 +841,28 @@ def test_no_end(self):
         assert lst == [*range(77, 177)]
 
 
+class TestRepeatMethod:
+    def test_repeat(self):
+        en = Enumerable.repeat('a', 5)
+        assert en.to_list() == ['a'] * 5
+
+    def test_no_elem(self):
+        en = Enumerable.repeat('g', 0)
+        assert en.to_list() == []
+
+    def test_1_elem(self):
+        en = Enumerable.repeat('x', 1)
+        assert en.to_list() == ['x']
+
+    def test_invalid(self):
+        with pytest.raises(ValueError):
+            Enumerable.repeat(99, -1)
+
+    def test_no_end(self):
+        hellos = Enumerable.repeat((), None).take(107)
+        assert hellos.to_list() == [()] * 107
+
+
 class TestSelectMethod:
     def test_select(self):
         gen_func = lambda: (i for i in range(4))

types_linq/enumerable.py

@@ -538,6 +538,21 @@ def inner(curr=start):
                     curr += 1
         return Enumerable(inner)
 
+    @staticmethod
+    def repeat(value: TResult, count: Optional[int] = None) -> Enumerable[TResult]:
+        if count is not None:
+            if count < 0:
+                raise ValueError('count must be nonnegative')
+            def inner(val=value, cnt=count):
+                while cnt > 0:
+                    yield val
+                    cnt -= 1
+        else:
+            def inner(val=value):
+                while True:
+                    yield val
+        return Enumerable(inner)
+
     def reverse(self) -> Enumerable[TSource_co]:
         return Enumerable(lambda: self._reversed_impl(fallback=True))
 

types_linq/enumerable.pyi

@@ -3,7 +3,7 @@ from typing import Callable, Dict, Generic, Iterable, Iterator, List, Optional,
 from .lookup import Lookup
 from .grouping import Grouping
 from .ordered_enumerable import OrderedEnumerable
-from .more_typing import SupportsAverage
+from .more_typing import SupportsAverage, TResult
 from .more_typing import (
     TAccumulate,
     TCollection,
@@ -480,7 +480,14 @@ class Enumerable(Sequence[TSource_co], Generic[TSource_co]):
         If `count` is `None`, the sequence is infinite.
         '''
 
-    # @@@ TODO
+    # count: Optional[int] is nonstandard behavior
+    @staticmethod
+    def repeat(value: TResult, count: Optional[int] = None) -> Enumerable[TResult]:
+        '''
+        Generates a sequence that contains one repeated value.
+
+        If `count` is `None`, the sequence is infinite.
+        '''
 
     def reverse(self) -> Enumerable[TSource_co]:
         '''