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How to initialize a private static const map in C++?
... int>’ as ‘this’ argument of ‘std::map<_Key, _Tp, _Compare, _Alloc>::mapped_type& std::map<_Key, _Tp, _Compare, _Alloc>::operator[](const key_type&) [with _Key = int; _Tp = int; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, int>...
How do I calculate a point on a circle’s circumference?
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Note that a must be in radians - that was really hard for me as a beginner to understand.
– ioan
Jun 2 '13 at 20:55
13
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Postgres: clear entire database before re-creating / re-populating from bash script
...elopment_db_name
$ createdb developmnent_db_name
That's how I do it, actually.
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How to find all the subclasses of a class given its name?
I need a working approach of getting all classes that are inherited from a base class in Python.
10 Answers
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Change working directory in my current shell context when running Node script
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The correct way to change directories is actually with process.chdir(directory). Here's an example from the documentation:
console.log('Starting directory: ' + process.cwd());
try {
process.chdir('/tmp');
console.log('New directory: ' + process.cwd());
}
catch (err...
What are the git concepts of HEAD, master, origin?
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I highly recommend the book "Pro Git" by Scott Chacon. Take time and really read it, while exploring an actual git repo as you do.
HEAD: the current commit your repo is on. Most of the time HEAD points to the latest commit in your current branch, but that doesn't have to be the case. HEAD rea...
Auto-loading lib files in Rails 4
.../foo.rb:
class Foo
end
in lib/foo/bar.rb:
class Foo::Bar
end
if you really wanna do some monkey patches in file like lib/extensions.rb, you may manually require it:
in config/initializers/require.rb:
require "#{Rails.root}/lib/extensions"
P.S.
Rails 3 Autoload Modules/Classes by Bill H...
What do the f and t commands do in Vim?
... information but people keep telling me that they are very useful. Would really appreciate an answer with an example if possible, thanks!
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Why sizeof int is wrong, while sizeof(int) is right?
...ans If we start trying to justify every decision made in C99 we'll be here all year. Quoting the standard is as good a way as any to wrap up this discussion.
– Perry
Oct 30 '12 at 18:50
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What is the most efficient way to create a dictionary of two pandas Dataframe columns?
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I found a faster way to solve the problem, at least on realistically large datasets using:
df.set_index(KEY).to_dict()[VALUE]
Proof on 50,000 rows:
df = pd.DataFrame(np.random.randint(32, 120, 100000).reshape(50000,2),columns=list('AB'))
df['A'] = df['A'].apply(chr)
%timeit dict(zip(df...