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What is Java String interning?
...gs will ensure that all strings having same contents share same memory. So if you have list of names where 'john' appears 1000 times, by interning you ensure only one 'john' is actually allocated memory.
This can be useful to reduce memory requirements of your program. But be aware that the cache i...
How can I get the max (or min) value in a vector?
...ud), myend(cloud)) << '\n';
}
Oh, and use std::minmax_element(...) if you need both at once :/
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What is the EAFP principle in Python?
...e assumes the existence of valid keys or attributes and catches exceptions if the assumption proves false. This clean and fast style is characterized by the presence of many try and except statements. The technique contrasts with the LBYL style common to many other languages such as C.
An example ...
Remove elements from collection while iterating
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Let me give a few examples with some alternatives to avoid a ConcurrentModificationException.
Suppose we have the following collection of books
List<Book> books = new ArrayList<Book>();
books.add(new Book(new ISBN("0-201-63361-2")));
books.add(new Book(new ISBN("0-201-63361-3")));
boo...
Get the index of the nth occurrence of a string?
...t of n method invocations - you won't actually be checking any case twice, if you think about it. (IndexOf will return as soon as it finds the match, and you'll keep going from where it left off.)
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Replace only some groups with Regex
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A good idea could be to encapsulate everything inside groups, no matter if need to identify them or not. That way you can use them in your replacement string. For example:
var pattern = @"(-)(\d+)(-)";
var replaced = Regex.Replace(text, pattern, "$1AA$3");
or using a MatchEvaluator:
var repl...
Finding Number of Cores in Java
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int cores = Runtime.getRuntime().availableProcessors();
If cores is less than one, either your processor is about to die, or your JVM has a serious bug in it, or the universe is about to blow up.
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How do I check if there are duplicates in a flat list?
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Use set() to remove duplicates if all values are hashable:
>>> your_list = ['one', 'two', 'one']
>>> len(your_list) != len(set(your_list))
True
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ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.al
...understood way to evaluate
an array in boolean context: it could mean True if any element is
True, or it could mean True if all elements are True, or True if the array has non-zero length, just to name three possibilities.
Since different users might have different needs and different assumptions, ...
Uninitialized constant ActiveSupport::Dependencies::Mutex (NameError)
...s with RubyGems 1.6.0+ and Rails < 2.3.11:
gem update --system 1.5.3
If you had previously downgraded to an even earlier version and want to update to 1.5.3, you might get the following when trying to run that:
Updating RubyGems
ERROR: While executing gem ... (RuntimeError)
No gem names ...