python 的可变长度参数 (*args) 是否在函数调用时扩展生成器？
考虑以下 Python 代码：
def f(*args):
for a in args:
pass
foo = ['foo', 'bar', 'baz']
# Python generator expressions FTW
gen = (f for f in foo)
f(*gen)
*args 是否在调用时自动扩展生成器？换句话说，我是否在 f(*gen) 内迭代 gen 两次，一次扩展 *args 一次迭代 args？或者生成器是否保持原始状态，而迭代仅在 for 循环期间发生一次？
Consider the following Python code:
def f(*args):
for a in args:
pass
foo = ['foo', 'bar', 'baz']
# Python generator expressions FTW
gen = (f for f in foo)
f(*gen)
Does *args automatically expand the generator at call-time? Put another way, am I iterating over gen twice within f(*gen), once to expand *args and once to iterate over args? Or is the generator preserved in pristine condition, while iteration only happens once during the for loop?
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生成器在函数调用时展开，您可以轻松检查：
将打印
The generator is expanded at the time of the function call, as you can easily check:
will print
为什么不看看
f()中的gen是什么？添加print args作为第一行。如果它仍然是一个生成器对象，它会告诉你。我希望参数解包将其变成一个元组。Why not look and see what
genis inf()? Addprint argsas the first line. If it's still a generator object, it'll tell you. I would expect the argument unpacking to turn it into a tuple.你并不真正需要
Calling
将输出
Your don't really need
Calling
will output