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What is the difference between float and double?
I've read about the difference between double precision and single precision. However, in most cases, float and double seem to be interchangeable, i.e. using one or the other does not seem to affect the results. Is this really the case? When are floats and doubles interchangeable? What are the d...
What is the best way to implement nested dictionaries?
...ython?
This is a bad idea, don't do it. Instead, use a regular dictionary and use dict.setdefault where apropos, so when keys are missing under normal usage you get the expected KeyError. If you insist on getting this behavior, here's how to shoot yourself in the foot:
Implement __missing__ on a di...
Why does X[Y] join of data.tables not allow a full outer join, or a left join?
...f a philosophical question about data.table join syntax. I am finding more and more uses for data.tables, but still learning...
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What characters are allowed in an email address?
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See RFC 5322: Internet Message Format and, to a lesser extent, RFC 5321: Simple Mail Transfer Protocol.
RFC 822 also covers email addresses, but it deals mostly with its structure:
addr-spec = local-part "@" domain ; global address
local-part ...
What is the difference between Cygwin and MinGW?
I want to make my C++ project cross platform, and I'm considering using Cygwin/MinGW.
But what is the difference between them ?
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Why shouldn't I use “Hungarian Notation”?
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Most people use Hungarian notation in a wrong way and are getting wrong results.
Read this excellent article by Joel Spolsky: Making Wrong Code Look Wrong.
In short, Hungarian Notation where you prefix your variable names with their type (string) (Systems Hungarian) is ba...
Should I always use a parallel stream when possible?
With Java 8 and lambdas it's easy to iterate over collections as streams, and just as easy to use a parallel stream. Two examples from the docs , the second one using parallelStream:
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Regular expression to check if password is “8 characters including 1 uppercase letter, 1 special cha
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The regular expression you are after will most likely be huge and a nightmare to maintain especially for people who are not that familiar with regular expressions.
I think it would be easier to break your regex down and do it one bit at a time. It might take a bit more to do, but I am ...
Why do people say that Ruby is slow? [closed]
I like Ruby on Rails and I use it for all my web development projects. A few years ago there was a lot of talk about Rails being a memory hog and about how it didn't scale very well but these suggestions were put to bed by Gregg Pollack here.
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What is the most effective way for float and double comparison?
...ing problems were:
The implicit presumption in an algorithm that if a==b and b==c then a==c.
Using the same epsilon for lines measured in inches and lines measured in mils (.001 inch). That is a==b but 1000a!=1000b. (This is why AlmostEqual2sComplement asks for the epsilon or max ULPS).
The use o...