擅长:python、mysql、java
<p>是的,使用字符串的<code>count</code>方法可以很容易地在一行中得到解决方案:</p>
<pre><code>>>> # I named it 'mystr' because it is a bad practice to name a variable 'str'
>>> # Doing so overrides the built-in
>>> mystr = "Hello! My name is Barney!"
>>> mystr.count("!")
2
>>> if mystr.count("!") == 2:
... print True
...
True
>>>
>>> # Just to explain further
>>> help(str.count)
Help on method_descriptor:
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.
>>>
</code></pre>