blocks|key|217857|text|我不确定这是否是Eclipse特有的东西，但我通常使用'_'来表示我不关心的值(即，在元组中返回值，或者在for-loops中使用索引值)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|217858|当然，您总是可以求助于旧的备用方法，比如命名变量dummy或ignore。|217859|我不确定PEP+8是否提到了这方面的任何东西，也许值得一看。|217860|entityMap|0|LINK|mutability|MUTABLE|url|http://www.python.org/dev/peps/pep-0008/^0|R|3|1H|3|0|O|5|U|6|0|4|5|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]|$9|U|A|V|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|11|8|@]|D|@$9|12|A|13|1|14]]|E|$]]|$1|J|3|-4|5|6|7|15|8|@]|D|@]|E|$]]]|K|$L|$5|M|N|O|E|$P|Q]]]]

Not sure if this is a Eclipse thing or not, but I generally use <code>'_'</code> to denote values I don't care about (i.e., return values in tuples, or index values in <code>for</code>-loops).

Of course you can always resort to old stand-bys like naming variables <code>dummy</code> or <code>ignore</code>.

I'm not sure if <a href="http://www.python.org/dev/peps/pep-0008/">PEP 8</a> mentions anything about this, might be worth peeking into.

blocks|key|223046|text|您几乎可以通过_1获得它。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|223047|223048|一个前导下划线的意思是，是的，这是存在的，你可以查看它，但是另一个方法或属性是你应该使用的；请参考文档。|unordered-list-item|223049|两个前导下划线的意思是，危险！不要触摸，否则会严重破坏事物的状态和稳定性。请远离它；如果你弄乱了它，如果出了什么问题，那都是你自己的错。|223050|223051|注意:使用__不仅仅是一种命名约定，因为它会导致name+mangling。这会将该变量重命名为_ClassName__var。这使得变量/方法更难在类外部使用。这样做主要是为了避免继承类意外重写父类中的方法。|223052|entityMap|0|LINK|mutability|MUTABLE|url|http://python.robasworld.com/private-member-name-mangling/^0|7|2|0|0|0|0|0|5|2|1C|F|O|D|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]|$1|G|3|H|5|I|7|10|8|@]|D|@]|E|$]]|$1|J|3|K|5|I|7|11|8|@]|D|@]|E|$]]|$1|L|3|-4|5|6|7|12|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|13|8|@$9|14|A|15|B|C]|$9|16|A|17|B|C]]|D|@$9|18|A|19|1|1A]]|E|$]]|$1|O|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

You pretty much got it with the <code>_1</code>:

<ul>
<li>one leading underscore means, yes, this exists, and you can look at it, but another method or property is what you should use instead; consult the docs.</li>
<li>two leading underscores means, danger! Do not touch or you will seriously break the state and stability of things. Please stay away; if you mess with it, it's all your own fault if something goes wrong. </li>
</ul>

Note: Using <code>__</code> is more than just a naming convention as it causes <a href="http://python.robasworld.com/private-member-name-mangling/" rel="nofollow noreferrer">name mangling</a>. This renames the variable to <code>_ClassName__var</code>. That makes the variable/method harder to use outside of the class. It's primarily done to avoid accidental overrides of methods in parent classes by inherited classes.

blocks|key|221290|text|是的，这是一个Python编码约定。最佳实践是在您不关心设置值的地方使用_，例如当unpacking+values+from+a+tuple时。然而，有时需要它是一种迹象，表明您可能正在以非Pythonic的方式做其他事情。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|221291|_作为前缀用于表示“私有”方法和变量，就像Phil+Cooper所说的那样。使用它来表明这些方法不是其他模块可以或应该依赖的任何公共契约的一部分。|221292|一些参考资料：|221293|221294|What+is+the+purpose+of+the+single+underscore+"_"+variable+in+Python?|unordered-list-item|221295|Underscores+as+function+prefixes|221296|What+is+the+meaning+of+a+single-+and+a+double-underscore+before+an+object+name?|221297|Why+does+python+use+two+underscores+for+certain+things?|221298|221299|entityMap|0|LINK|mutability|MUTABLE|url|https://www.python.org/dev/peps/pep-3132/|1|https://stackoverflow.com/questions/5893163/underscore-in-python|2|https://docs.python.org/3/reference/lexical_analysis.html#reserved-classes-of-identifiers|3|https://stackoverflow.com/questions/1301346/the-meaning-of-a-single-and-a-double-underscore-before-an-object-name-in-python|4|https://stackoverflow.com/questions/3443043/why-does-python-use-two-underscores-for-certain-things^0|10|1|15|T|0|0|0|1|0|0|0|0|1W|1|0|0|W|2|0|0|27|3|0|0|1J|4|0|0^^$0|@$1|2|3|4|5|6|7|1A|8|@$9|1B|A|1C|B|C]]|D|@$9|1D|A|1E|1|1F]]|E|$]]|$1|F|3|G|5|6|7|1G|8|@$9|1H|A|1I|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|1J|8|@]|D|@]|E|$]]|$1|J|3|-4|5|6|7|1K|8|@]|D|@]|E|$]]|$1|K|3|L|5|M|7|1L|8|@]|D|@$9|1M|A|1N|1|1O]]|E|$]]|$1|N|3|O|5|M|7|1P|8|@]|D|@$9|1Q|A|1R|1|1S]]|E|$]]|$1|P|3|Q|5|M|7|1T|8|@]|D|@$9|1U|A|1V|1|1W]]|E|$]]|$1|R|3|S|5|M|7|1X|8|@]|D|@$9|1Y|A|1Z|1|20]]|E|$]]|$1|T|3|-4|5|6|7|21|8|@]|D|@]|E|$]]|$1|U|3|-4|5|6|7|22|8|@]|D|@]|E|$]]]|V|$W|$5|X|Y|Z|E|$10|11]]|12|$5|X|Y|Z|E|$10|13]]|14|$5|X|Y|Z|E|$10|15]]|16|$5|X|Y|Z|E|$10|17]]|18|$5|X|Y|Z|E|$10|19]]]]

This is a Python coding convention, yes. Best practice is to use <code>_</code> where you don't care about the value being set, for example when <a href="https://www.python.org/dev/peps/pep-3132/" rel="noreferrer">unpacking values from a tuple</a>. Sometimes, however, needing this is a sign you may be doing something else in a non-Pythonic way.

<code>_</code> as a prefix is used to indicate "private" methods and variables, like Phil Cooper said. Use this to indicate that these methods are not part of any public contract other modules can or should rely on.

Some references:

<ul>
<li><a href="https://stackoverflow.com/questions/5893163/underscore-in-python">What is the purpose of the single underscore &quot;_&quot; variable in Python?</a></li>
<li><a href="https://docs.python.org/3/reference/lexical_analysis.html#reserved-classes-of-identifiers" rel="noreferrer">Underscores as function prefixes</a></li>
<li><a href="https://stackoverflow.com/questions/1301346/the-meaning-of-a-single-and-a-double-underscore-before-an-object-name-in-python">What is the meaning of a single- and a double-underscore before an object name?</a></li>
<li><a href="https://stackoverflow.com/questions/3443043/why-does-python-use-two-underscores-for-certain-things">Why does python use two underscores for certain things?</a></li>
</ul>

blocks|key|217916|text|让我们从..。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|217917|>>>+import+this
The+Zen+of+Python,+by+Tim+Peters

Beautiful+is+better+than+ugly.
...
Readability+counts.
Special+cases+aren't+special+enough+to+break+the+rules.|code-block|syntax|javascript|217918|我建议选择不成问题的方法。它通常意味着某种自我解释的、简单的和可理解的东西。如果你坚持要表达not+used，那么unused或者dummy这个名字呢？|offset|length|style|CODE|217919|如果可能的话，_应该变得更隐蔽、隐藏，甚至是被忽视的候选对象吗？|217920|对于Perl用户来说，_不仅仅意味着未使用的东西。即使您可能不关心Perl用户，但是如果您以前从未见过_，那么它对您意味着什么呢？|217921|entityMap^0|0|0|1L|6|1T|5|0|7|1|0|B|1|1F|1|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@$I|V|J|W|K|L]|$I|X|J|Y|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|Z|8|@$I|10|J|11|K|L]]|9|@]|A|$]]|$1|O|3|P|5|6|7|12|8|@$I|13|J|14|K|L]|$I|15|J|16|K|L]]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|R|$]]

Let's start with...

<pre><code>&gt;&gt;&gt; import this
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
...
Readability counts.
Special cases aren't special enough to break the rules.
</code></pre>

I recommend to choose the approach that is not questionable. It usually means something that is self-explainable, simple and understandable. If you insist on expressing the not used, what about the name <code>unused</code> or <code>dummy</code>? 

Should the <code>_</code> be more invisible, hidden or even the candidate for to be overlooked, if possible?

For Perl users, the <code>_</code> means something else than unused. Even though you may not care about the Perl users, what would the <code>_</code> mean for you if you never met it before?

<blockquote>
 Possible Duplicate: 
 <a href="https://stackoverflow.com/questions/5477134/how-can-i-get-around-declaring-an-unused-variable-in-a-for-loop">How can I get around declaring an unused variable in a for loop?</a> 
</blockquote>



In Python what is the best practice for naming a variable that is not going to be used? This is an odd question sure, but for my specific case I have a tuple of (key, value) where I am only interested in the value. A basic demo of my use case:

<pre><code>some_stuff = [("key", "value"), ("key2", "value")]
for _, value in some_stuff:
 pass # TODO: do something really important with value
</code></pre>

I've noticed in Eclipse that naming a variable _ or with an _ prefix (e.g. _k) will not show an unused variable warning and removing the _ prefix causes the warning to be raised, but this may just be an oddity/"feature" in Eclipse rather than Python best practice..

Unused variable naming in python

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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 可能重复：在Python中，命名不会使用的变量的最佳实践是什么？这确实是一个奇怪的问题，但对于我的特定情况，我有一个元组(key，value)，其中我只对值感兴趣。我的用例的基本演示：some_stuff = [("key", "value"), ("key2", "value")]for _, value in s...

问python中未使用的变量命名
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