python 如何计算某个字符串中某事发生的次数？
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How to count the number of times something occurs inside a certain string?
提问by TIMEX
In python, I remember there is a function to do this.
在python中，我记得有一个函数可以做到这一点。
.count?
。数数？
"The big brown fox is brown" brown = 2.
“棕色的大狐狸是棕色的”棕色 = 2。
回答by ghostdog74
why not read the docs first, it's very simple:
为什么不先阅读文档，很简单：
>>> "The big brown fox is brown".count("brown")
2
回答by Dave Webb
One thing worth learning if you're a Python beginner is how to use interactive modeto help with this. The first thing to learn is the dirfunctionwhich will tell you the attributes of an object.
如果您是 Python 初学者，值得学习的一件事是如何使用交互模式来帮助解决这个问题。首先要学习的是dir函数，它会告诉你一个对象的属性。
>>> mystring = "The big brown fox is brown"
>>> dir(mystring)
['__add__', '__class__', '__contains__', '__delattr__', '__doc__', '__eq__', '__
ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__getslice__', '__g
t__', '__hash__', '__init__', '__le__', '__len__', '__lt__', '__mod__', '__mul__
', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '
__rmul__', '__setattr__', '__str__', 'capitalize', 'center', 'count', 'decode',
'encode', 'endswith', 'expandtabs', 'find', 'index', 'isalnum', 'isalpha', 'isdi
git', 'islower', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lst
rip', 'partition', 'replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit'
, 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', '
translate', 'upper', 'zfill']
Remember, in Python, methods are also attributes. So now he use the helpfunctionto inquire about one of the methods that looks promising:
请记住，在 Python 中，方法也是属性。所以现在他用help函数来查询一个看起来很有前景的方法：
>>> help(mystring.count)
Help on built-in function count:
count(...)
S.count(sub[, start[, end]]) -> int
Return the number of non-overlapping occurrences of substring sub in
string S[start:end]. Optional arguments start and end are interpreted
as in slice notation.
This displays the docstringof the method - some help text which you should get in to the habit of putting in your own methods too.
这将显示方法的文档字符串——一些帮助文本，您也应该养成放入自己的方法的习惯。
