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Return None if Dictionary key is not available
...f __getitem__(self, key):
return dict.get(self, key)
>>> foo = NoneDict([(1,"asdf"), (2,"qwerty")])
>>> foo[1]
'asdf'
>>> foo[2]
'qwerty'
>>> foo[3] is None
True
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Constructor overload in TypeScript
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TypeScript allows you to declare overloads but you can only have one implementation and that implementation must have a signature that is compatible with all overloads. In your example, this can easily be done with an optional parameter...
Why have header files and .cpp files? [closed]
...dencies so that code that uses the header doesn't necessarily need to know all the details of the implementation and any other classes/headers needed only for that. This will reduce compilation times and also the amount of recompilation needed when something in the implementation changes.
It's not ...
What does %w(array) mean?
....], curly braces %w{...} or even something like exclamation marks %w!...!. All of these have the same behavior (returning an array).
– ryanb
Aug 13 '09 at 21:40
146
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Making 'git log' ignore changes for certain paths
...e as match_pathspec_depth_1() and for correctness was only supposed to be called from match_pathspec_depth(). match_pathspec_depth() was later renamed to match_pathspec(), so the invariant we expect today is that do_match_pathspec() has no direct callers outside of match_pathspec().
Unfortunately,...
How to sort an array in descending order in Ruby
... 0.001631 0.110628 ( 0.111532)
...the reverse method doesn't actually return a reversed array - it returns an enumerator that just starts at the end and works backwards.
The source for Array#reverse is:
static VALUE
rb_ary_reverse_m(VALUE ary)
{
long len = RARRAY_LEN(...
Is there a better way to express nested namespaces in C++ within the header
...
To avoid really deep indenting, I usually do it this way:
namespace A { namespace B { namespace C
{
class X
{
// ...
};
}}}
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How do I convert a String object into a Hash object?
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The string created by calling Hash#inspect can be turned back into a hash by calling eval on it. However, this requires the same to be true of all of the objects in the hash.
If I start with the hash {:a => Object.new}, then its string represen...
Get selected subcommand with argparse
...ser.add_subparsers(dest="subparser_name") # this line changed
>>> foo_parser = subparsers.add_parser('foo')
>>> foo_parser.add_argument('-c', '--count')
>>> bar_parser = subparsers.add_parser('bar')
>>> args = parser.parse_args(['-g', 'xyz', 'foo', '--count', '42'...
Understanding __get__ and __set__ and Python descriptors
...th the Temperature class). For example:
temp=Temperature()
temp.celsius #calls celsius.__get__
Accessing the property you assigned the descriptor to (celsius in the above example) calls the appropriate descriptor method.
instance in __get__ is the instance of the class (so above, __get__ would r...