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What is a non-capturing group in regular expressions?
How are non-capturing groups, i.e. (?:) , used in regular expressions and what are they good for?
15 Answers
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How can I repeat a character in Bash?
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You can use:
printf '=%.0s' {1..100}
How this works:
Bash expands {1..100} so the command becomes:
printf '=%.0s' 1 2 3 4 ... 100
I've set printf's format to =%.0s which means that it will always print a single = no matter what argument it is given. Therefore it prints 100 =s.
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Test if characters are in a string
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@GregSnow -- Tried system.time(a <- grepl("abc", vec)) and system.time(a <- grepl("abc", vec, fixed=TRUE)), and fixed=TRUE is still, if anything slightly slower. The difference isn't appreciable with these short strings, but fixed=TRUE still doesn't seem to be faster. Thanks ...
Underscore: sortBy() based on multiple attributes
...atient[0].roomNumber;
}).value();
When the second sortBy finds that John and Lisa have the same room number it will keep them in the order it found them, which the first sortBy set to "Lisa, John".
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jQuery deferreds and promises - .then() vs .done()
I've been reading about jQuery deferreds and promises and I can't see the difference between using .then() & .done() for successful callbacks. I know Eric Hynds mentions that .done() and .success() map to the same functionality but I'm guessing so does .then() as all the callbacks are al...
Proper stack and heap usage in C++?
I've been programming for a while but It's been mostly Java and C#. I've never actually had to manage memory on my own. I recently began programming in C++ and I'm a little confused as to when I should store things on the stack and when to store them on the heap.
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Using python map and other functional tools
This is quite n00bish, but I'm trying to learn/understand functional programming in python. The following code:
9 Answers
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Is there a difference between foreach and map?
...n a particular language, but is there a difference between a map operation and a foreach operation? Or are they simply different names for the same thing?
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Is there a valid reason for enforcing a maximum width of 80 characters in a code file, this day and
... column rule:
To avoid wrapping when copying code into email, web pages, and books.
To view multiple source windows side-by-side or using a side-by-side diff viewer.
To improve readability. Narrow code can be read quickly without having to scan your eyes from side to side.
I think the last point...
F# development and unit testing?
... first functional language. I have been working quasi-exclusively with C#, and enjoy a lot how F# leads me to re-think how I write code. One aspect I find a bit disorienting is the change in the process of writing code. I have been using TDD for years in C# now, and really appreciate to have unit te...