Issue
A generator can be iterated step by step by using the next()
built-in function. For example:
def sync_gen(n):
"""Simple generator"""
for i in range(n):
yield i**2
sg = sync_gen(4)
print(next(sg)) # -> 0
print(next(sg)) # -> 1
print(next(sg)) # -> 4
Using next()
on an asynchronous generator does not work:
import asyncio
async def async_gen(n):
for i in range(n):
yield i**2
async def main():
print("Async for:")
async for v in async_gen(4): # works as expected
print(v)
print("Async next:")
ag = async_gen(4)
v = await next(ag) # raises: TypeError: 'async_generator' object is not an iterator
print(v)
asyncio.run(main())
Does something like v = await async_next(ag)
exist to obtain same behavior as with normal generators?
Solution
PEP525 Asynchronous Generator Object describes __anext__()
method:
agen.__anext__()
: Returns an awaitable, that performs one asynchronous generator iteration when awaited.
So it's possible to call it:
print("Async next:")
ag = async_gen(4)
v = await ag.__anext__()
print(v)
But as discussed here it is not recommended
Answered By - ujlbu4
0 comments:
Post a Comment
Note: Only a member of this blog may post a comment.