擅长:python、mysql、java
<p>我相信当你写一个函数时,它的返回值应该是清晰的和预期的。你应该把你说要归还的东西归还。也就是说,您可以使用<code>None</code>作为有意义的返回值来指示操作失败或未产生任何结果:</p>
<pre><code>def doSomething():
"""
doSomething will return a string value
If there is no value available, None will be returned
"""
if check_something():
return "a string"
# this is being explicit. If you did not do this,
# None would still be returned. But it is nice
# to be verbose so it reads properly with intent.
return None
</code></pre>
<p>或者您可以确保始终返回相同类型的默认值:</p>
<pre><code>def doSomething():
"""
doSomething will return a string value
If there is no value available, and empty string
will be returned
"""
if check_something():
return "a string"
return ""
</code></pre>
<p>这将通过一系列复杂的条件测试来处理这个问题,这些测试最终会失败:</p>
<pre><code>def doSomething():
if foo:
if bar:
if biz:
return "value"
return ""
</code></pre>