迭代每个字符串？

Question

假设我有一个字符串，如：

Hello world

我想迭代每个字符，以便打印迭代：

H
He
Hel
Hell
Hello
Hello(space) 
Helllo W... etc

怎么可以这样做？

Answer 1

只需切片：

>>> mystr = 'Hello world'
>>> for i in range(len(mystr)+1):
...     print mystr[:i]
...

H
He
Hel
Hell
Hello
Hello
Hello w
Hello wo
Hello wor
Hello worl
Hello world
>>>

或者，一线解决方案：

>>> # This might be slower though if the string is massive
>>> print "\n".join([mystr[:i] for i in range(len(mystr)+1)])

H
He
Hel
Hell
Hello
Hello
Hello w
Hello wo
Hello wor
Hello worl
Hello world
>>>