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What does ** and * do for python parameters?
What does *args and **kwargs mean?
简单程序:
storyFormat = """
Once upon a time, deep in an ancient jungle,
there lived a {animal}. This {animal}
liked to eat {food}, but the jungle had
very little {food} to offer. One day, an
explorer found the {animal} and discovered
it liked {food}. The explorer took the
{animal} back to {city}, where it could
eat as much {food} as it wanted. However,
the {animal} became homesick, so the
explorer brought it back to the jungle,
leaving a large supply of {food}.
The End
"""
def tellStory():
userPicks = dict()
addPick('animal', userPicks)
addPick('food', userPicks)
addPick('city', userPicks)
story = storyFormat.format(**userPicks)
print(story)
def addPick(cue, dictionary):
'''Prompt for a user response using the cue string,
and place the cue-response pair in the dictionary.
'''
prompt = 'Enter an example for ' + cue + ': '
response = input(prompt).strip() # 3.2 Windows bug fix
dictionary[cue] = response
tellStory()
input("Press Enter to end the program.")
关注这一行:
story = storyFormat.format(**userPicks)
什么是**
的意思?为什么不直接通过一个简单的userPicks
?
**指克瓦格。这是一篇关于它的好文章。
读这个:http://www.saltycrane.com/blog/2008/01/how-to-use-args-and-kwargs-in-python/
“**”接受dict并提取其内容,并将其作为参数传递给函数。以这个函数为例:
现在通常可以这样调用此函数:
但您也可以用这些存储的参数填充字典,如下所示:
现在可以将此传递给函数:
有时您会在函数定义中看到这种格式:
*args
提取位置参数和**kwargs
提取关键字参数。相关问题 更多 >
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