I have a generator and I would like to know if I can use it without having to worry about StopIteration , and I would like to use it without the for item in generator
. I would like to use it with a while statement for example ( or other constructs ). How could I do that ?
我有一个发电机,我想知道我是否可以使用它而不必担心StopIteration,我想在没有发电机的for项目的情况下使用它。我想将它与while语句(或其他构造)一起使用。我怎么能这样做?
3 个解决方案
#1
-1
Use this to wrap your generator:
用它来包裹你的发电机:
class GeneratorWrap(object):
def __init__(self, generator):
self.generator = generator
def __iter__(self):
return self
def next(self):
for o in self.generator:
return o
raise StopIteration # If you don't care about the iterator protocol, remove this line and the __iter__ method.
Use it like this:
像这样用它:
def example_generator():
for i in [1,2,3,4,5]:
yield i
gen = GeneratorWrap(example_generator())
print gen.next() # prints 1
print gen.next() # prints 2
Update: Please use the answer below because it is much better than this one.
更新:请使用下面的答案,因为它比这个好得多。
#2
15
built-in function
内置功能
next(iterator[, default])
Retrieve the next item from the iterator by calling its__next__()
method. If default is given, it is returned if the iterator is exhausted, otherwise StopIteration is raised.next(iterator [,default])通过调用__next __()方法从迭代器中检索下一个项目。如果给定default,则在迭代器耗尽时返回,否则引发StopIteration。
In Python 2.5 and older:
在Python 2.5及更早版本中:
raiseStopIteration = object()
def next(iterator, default=raiseStopIteration):
if not hasattr(iterator, 'next'):
raise TypeError("not an iterator")
try:
return iterator.next()
except StopIteration:
if default is raiseStopIteration:
raise
else:
return default
#3
1
Another options is to read all generator values at once:
另一种选择是一次读取所有发生器值:
>>> alist = list(agenerator)
Example:
例:
>>> def f():
... yield 'a'
...
>>> a = list(f())
>>> a[0]
'a'
>>> len(a)
1
#1
-1
Use this to wrap your generator:
用它来包裹你的发电机:
class GeneratorWrap(object):
def __init__(self, generator):
self.generator = generator
def __iter__(self):
return self
def next(self):
for o in self.generator:
return o
raise StopIteration # If you don't care about the iterator protocol, remove this line and the __iter__ method.
Use it like this:
像这样用它:
def example_generator():
for i in [1,2,3,4,5]:
yield i
gen = GeneratorWrap(example_generator())
print gen.next() # prints 1
print gen.next() # prints 2
Update: Please use the answer below because it is much better than this one.
更新:请使用下面的答案,因为它比这个好得多。
#2
15
built-in function
内置功能
next(iterator[, default])
Retrieve the next item from the iterator by calling its__next__()
method. If default is given, it is returned if the iterator is exhausted, otherwise StopIteration is raised.next(iterator [,default])通过调用__next __()方法从迭代器中检索下一个项目。如果给定default,则在迭代器耗尽时返回,否则引发StopIteration。
In Python 2.5 and older:
在Python 2.5及更早版本中:
raiseStopIteration = object()
def next(iterator, default=raiseStopIteration):
if not hasattr(iterator, 'next'):
raise TypeError("not an iterator")
try:
return iterator.next()
except StopIteration:
if default is raiseStopIteration:
raise
else:
return default
#3
1
Another options is to read all generator values at once:
另一种选择是一次读取所有发生器值:
>>> alist = list(agenerator)
Example:
例:
>>> def f():
... yield 'a'
...
>>> a = list(f())
>>> a[0]
'a'
>>> len(a)
1