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Is it possible for a computer to “learn” a regular expression by user-provided examples?
...ton, it is possible to learn some regular expressions by a program. Kearns and Valiant show some cases where it is not possible to learn a finite automaton. A related problem is learning hidden Markov Models, which are probabilistic automata that can describe a character sequence. Note that most mod...
Most efficient way to check for DBNull and then assign to a variable?
...to avoid. By writing row.IsNull(columnName) you're reading it once already and reading it again. Not saying that will make a difference, but theoretically it can be less efficient..
– nawfal
Feb 6 '13 at 16:31
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What are the recommendations for html tag?
...re deciding whether to use the <base> tag or not, you need to understand how it works, what it can be used for and what the implications are and finally outweigh the advantages/disadvantages.
The <base> tag mainly eases creating relative links in templating languages as you don't need...
What's the difference between and in servlet
...ort for general annotations such as @Required, @Autowired, @PostConstruct, and so on.
<mvc:annotation-driven /> declares explicit support for annotation-driven MVC controllers (i.e. @RequestMapping, @Controller, although support for those is the default behaviour), as well as adding support f...
How do I get current date/time on the Windows command line in a suitable format for usage in a file/
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On my system %TIME% returns values like " 0:01:15" and " 3:15:12" and the %%a%%b code in the answer gives a leading space like " 001" and " 315". To get a four digit hhmm use this: For /f "tokens=1-2 delims=/: " %%a in ("%TIME%") do (if %%a LSS 10 (set mytime=0%%a%%b) else (s...
Mutable vs immutable objects
...returning an array of strings from a method) but I'm having trouble understanding what the negative impacts are of this. What are the best practices around using mutable objects? Should you avoid them whenever possible?
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When to use lambda, when to use Proc.new?
In Ruby 1.8, there are subtle differences between proc/lambda on the one hand, and Proc.new on the other.
14 Answers
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How can I create directory tree in C++/Linux?
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With C++17 or later, there's the standard header <filesystem> with
function
std::filesystem::create_directories
which should be used in modern C++ programs.
The C++ standard functions do not have the POSIX-specific explicit
permissions (mode) argument, t...
View markdown files offline [closed]
... referring to showing the README.md file as it would come out in Github, and not as for editing purposes.
34 Answers
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Why is extending native objects a bad practice?
... get a perfomance hit? Do they fear that somebody does it "the wrong way", and adds enumerable types to Object , practically destroying all loops on any object?
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