这仅适用于Python 3.2+:
>>> def gen(): yield 0; yield 1
...
>>> a = gen()
>>> import inspect
>>> inspect.getgeneratorstate(a)
'GEN_CREATED'
>>> next(a)
0
>>> inspect.getgeneratorstate(a)
'GEN_SUSPENDED'
>>> next(a)
1
>>> inspect.getgeneratorstate(a)
'GEN_SUSPENDED'
>>> next(a)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
StopIteration
>>> inspect.getgeneratorstate(a)
'GEN_CLOSED'
因此,请求的功能是:
import inspect
def is_just_started(gen):
return inspect.getgeneratorstate(gen) == inspect.GEN_CREATED:
出于好奇,我研究了cpython以弄清它是如何确定的……显然,它看起来generator.gi_frame.f_lasti
是“最后尝试的指令在字节码中的索引”。如果是,-1
那么它还没有开始。
这是py2版本:
def is_just_started(gen):
return gen.gi_frame is not None and gen.gi_frame.f_lasti == -1