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What is a regular expression for a MAC Address?

...at" comes from Wikipedia, not the 802.3 standards body. IEEE 802-2014 actually specifies hyphens for ordinary MAC addresses (§ 8.1 ¶ 3) and colons for the obsolescent bit-reversed notation (¶ 4). Importantly, in practice, no one observes this. We simply use one or the other, but never mix them...
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List changes unexpectedly after assignment. How do I clone or copy it to prevent this?

... With new_list = my_list, you don't actually have two lists. The assignment just copies the reference to the list, not the actual list, so both new_list and my_list refer to the same list after the assignment. To actually copy the list, you have various possibilit...
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Can I change a private readonly field in C# using reflection?

...am not aware of any place where we document that readonly fields must be mutable via reflection. As far as I know, a conforming implementation of the CLI is perfectly free to implement readonly fields such that they throw exceptions when mutated via reflection after the constructor is done. ...
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Tuples( or arrays ) as Dictionary keys in C#

I am trying to make a Dictionary lookup table in C#. I need to resolve a 3-tuple of values to one string. I tried using arrays as keys, but that did not work, and I don't know what else to do. At this point I am considering making a Dictionary of Dictionaries of Dictionaries, but that would proba...
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No mapping found for field in order to sort on in ElasticSearch

... I still have the problem but I want the documents to be in the results in all cases even if they don't have the attribute. – c4k Oct 27 '13 at 15:47 ...
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Comparing mongoose _id and strings

... The accepted answers really limit what you can do with your code. For example, you would not be able to search an array of Object Ids by using the equals method. Instead, it would make more sense to always cast to string and compare the keys. Her...
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Viewing all defined variables [duplicate]

...ython shell. What I want to have is Matlab style listout where you can see all the variables that have been defined up to a point (so I know which names I've used, their values and such). ...
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how to customize `show processlist` in mysql?

...ou can ORDER BY in any way you like. The INFORMATION_SCHEMA.PROCESSLIST table was added in MySQL 5.1.7. You can find out which version you're using with: SELECT VERSION() share | improve this ...
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How do I replace whitespaces with underscore?

...s, such as \t or a non-breaking space. – Roberto Bonvallet Jun 17 '09 at 15:49 13 Yes you are cor...
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Multiple constructors in python? [duplicate]

... Now you can do: c = C(fd) # or: c = C.fromfilename('a filename') Notice all those classmethods still go through the same __init__, but using classmethods can be much more convenient than having to remember what combinations of keyword arguments to __init__ work. isinstance is best avoided becaus...