diff options
Diffstat (limited to 'Doc')
| -rw-r--r-- | Doc/glossary.rst | 13 | ||||
| -rw-r--r-- | Doc/howto/functional.rst | 40 | ||||
| -rw-r--r-- | Doc/reference/expressions.rst | 4 |
3 files changed, 29 insertions, 28 deletions
diff --git a/Doc/glossary.rst b/Doc/glossary.rst index 3caa36e..f7a4b569 100644 --- a/Doc/glossary.rst +++ b/Doc/glossary.rst @@ -168,7 +168,7 @@ Glossary :keyword:`yield` elements back to the caller. The function execution is stopped at the :keyword:`yield` keyword (returning the result) and is resumed there when the next element is requested by calling the - :meth:`next` method of the returned iterator. + :meth:`__next__` method of the returned iterator. .. index:: single: generator expression @@ -266,11 +266,12 @@ Glossary iterator An object representing a stream of data. Repeated calls to the iterator's - :meth:`next` method return successive items in the stream. When no more - data is available a :exc:`StopIteration` exception is raised instead. At - this point, the iterator object is exhausted and any further calls to its - :meth:`next` method just raise :exc:`StopIteration` again. Iterators are - required to have an :meth:`__iter__` method that returns the iterator + :meth:`__next__` (or passing it to the builtin function) :func:`next` + method return successive items in the stream. When no more data is + available a :exc:`StopIteration` exception is raised instead. At this + point, the iterator object is exhausted and any further calls to its + :meth:`__next__` method just raise :exc:`StopIteration` again. Iterators + are required to have an :meth:`__iter__` method that returns the iterator object itself so every iterator is also iterable and may be used in most places where other iterables are accepted. One notable exception is code that attempts multiple iteration passes. A container object (such as a diff --git a/Doc/howto/functional.rst b/Doc/howto/functional.rst index c71d038..3ba5e8b 100644 --- a/Doc/howto/functional.rst +++ b/Doc/howto/functional.rst @@ -184,11 +184,11 @@ foundation for writing functional-style programs: iterators. An iterator is an object representing a stream of data; this object returns the data one element at a time. A Python iterator must support a method called -``next()`` that takes no arguments and always returns the next element of the -stream. If there are no more elements in the stream, ``next()`` must raise the -``StopIteration`` exception. Iterators don't have to be finite, though; it's -perfectly reasonable to write an iterator that produces an infinite stream of -data. +``__next__()`` that takes no arguments and always returns the next element of +the stream. If there are no more elements in the stream, ``__next__()`` must +raise the ``StopIteration`` exception. Iterators don't have to be finite, +though; it's perfectly reasonable to write an iterator that produces an infinite +stream of data. The built-in :func:`iter` function takes an arbitrary object and tries to return an iterator that will return the object's contents or elements, raising @@ -203,13 +203,13 @@ You can experiment with the iteration interface manually: >>> it = iter(L) >>> it <...iterator object at ...> - >>> it.next() + >>> it.__next__() 1 - >>> it.next() + >>> next(it) 2 - >>> it.next() + >>> next(it) 3 - >>> it.next() + >>> next(it) Traceback (most recent call last): File "<stdin>", line 1, in ? StopIteration @@ -467,20 +467,20 @@ the ``yield`` expression, the generator outputs the value of ``i``, similar to a ``return`` statement. The big difference between ``yield`` and a ``return`` statement is that on reaching a ``yield`` the generator's state of execution is suspended and local variables are preserved. On the next call to the -generator's ``.next()`` method, the function will resume executing. +generator's ``.__next__()`` method, the function will resume executing. Here's a sample usage of the ``generate_ints()`` generator: >>> gen = generate_ints(3) >>> gen <generator object at ...> - >>> gen.next() + >>> next(gen) 0 - >>> gen.next() + >>> next(gen) 1 - >>> gen.next() + >>> next(gen) 2 - >>> gen.next() + >>> next(gen) Traceback (most recent call last): File "stdin", line 1, in ? File "stdin", line 2, in generate_ints @@ -500,7 +500,7 @@ the bottom of the function. You could achieve the effect of generators manually by writing your own class and storing all the local variables of the generator as instance variables. For example, returning a list of integers could be done by setting ``self.count`` to -0, and having the ``next()`` method increment ``self.count`` and return it. +0, and having the ``__next__()`` method increment ``self.count`` and return it. However, for a moderately complicated generator, writing a corresponding class can be much messier. @@ -555,7 +555,7 @@ but have to use parentheses when there's an operation, as in ``val = (yield i) Values are sent into a generator by calling its ``send(value)`` method. This method resumes the generator's code and the ``yield`` expression returns the -specified value. If the regular ``next()`` method is called, the ``yield`` +specified value. If the regular ``__next__()`` method is called, the ``yield`` returns ``None``. Here's a simple counter that increments by 1 and allows changing the value of @@ -576,15 +576,15 @@ the internal counter. And here's an example of changing the counter: >>> it = counter(10) - >>> it.next() + >>> next(it) 0 - >>> it.next() + >>> next(it) 1 >>> it.send(8) 8 - >>> it.next() + >>> next(it) 9 - >>> it.next() + >>> next(it) Traceback (most recent call last): File ``t.py'', line 15, in ? it.next() diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst index e205e42..43b0bf4 100644 --- a/Doc/reference/expressions.rst +++ b/Doc/reference/expressions.rst @@ -375,8 +375,8 @@ generator function: Starts the execution of a generator function or resumes it at the last executed :keyword:`yield` expression. When a generator function is resumed - with a :meth:`next` method, the current :keyword:`yield` expression always - evaluates to :const:`None`. The execution then continues to the next + with a :meth:`__next__` method, the current :keyword:`yield` expression + always evaluates to :const:`None`. The execution then continues to the next :keyword:`yield` expression, where the generator is suspended again, and the value of the :token:`expression_list` is returned to :meth:`next`'s caller. If the generator exits without yielding another value, a :exc:`StopIteration` |