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Removing multiple keys from a dictionary safely
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Why not like this:
entries = ('a', 'b', 'c')
the_dict = {'b': 'foo'}
def entries_to_remove(entries, the_dict):
for key in entries:
if key in the_dict:
del the_dict[key]
A more compact version was provided by mattbornski using dict.pop...
Is it more efficient to copy a vector by reserving and copying, or by creating and swapping? [duplic
I am trying to efficiently make a copy of a vector. I see two possible approaches:
7 Answers
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C++, variable declaration in 'if' expression
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As of C++17 what you were trying to do is finally possible:
if (int a = Func1(), b = Func2(); a && b)
{
// Do stuff with a and b.
}
Note the use of ; of instead of , to separate the declaration and the actual condition.
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pandas read_csv and filter columns with usecols
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The answer by @chip completely misses the point of two keyword arguments.
names is only necessary when there is no header and you want to specify other arguments using column names rather than integer indices.
usecols is supposed to p...
Why is `std::move` named `std::move`?
...mes confuses people. However the intent of this naming is not to confuse, but rather to make your code more readable.
The history of move dates back to the original move proposal in 2002. This paper first introduces the rvalue reference, and then shows how to write a more efficient std::swap:
te...
C++11 rvalues and move semantics confusion (return statement)
... = return_vector();
The first example returns a temporary which is caught by rval_ref. That temporary will have its life extended beyond the rval_ref definition and you can use it as if you had caught it by value. This is very similar to the following:
const std::vector<int>& rval_ref = ...
Add column with number of days between dates in DataFrame pandas
I want to subtract dates in 'A' from dates in 'B' and add a new column with the difference.
4 Answers
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Difference between git checkout --track origin/branch and git checkout -b branch origin/branch
Does anybody know the difference between these two commands to switch and track a remote branch?
4 Answers
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What is the fastest way to get the value of π?
I'm looking for the fastest way to obtain the value of π, as a personal challenge. More specifically, I'm using ways that don't involve using #define constants like M_PI , or hard-coding the number in.
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Pass all variables from one shell script to another?
Lets say I have a shell / bash script named test.sh with:
7 Answers
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