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Using member variable in lambda capture list inside a member function
... grid is not in the enclosing scope, but this is (every access to grid actually happens as this->grid in member functions). For your usecase, capturing this works, since you'll use it right away and you don't want to copy the grid
auto lambda = [this](){ std::cout << grid[0][0] << "\...
add a string prefix to each value in a string column using Pandas
...map :
df['col'].map('str{}'.format)
It will apply the word "str" before all your values.
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How does grep run so fast?
I am really amazed by the functionality of GREP in shell, earlier I used to use substring method in java but now I use GREP for it and it executes in a matter of seconds, it is blazingly faster than java code that I used to write.(according to my experience I might be wrong though)
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Define preprocessor macro through CMake?
... place for add_definitions. CMake is such a shabby system, but they are finally finding some sanity.
Find more explanation on which commands to use for compiler flags here: https://cmake.org/cmake/help/latest/command/add_definitions.html
Likewise, you can do this per-target as explained in Jim Hun...
Case in Select Statement
...imple CASE expression
Within a SELECT statement, a simple CASE expression allows for only an equality check; no other comparisons are made. The following example uses the CASE expression to change the display of product line categories to make them more understandable.
USE AdventureWorks2012;
GO
S...
Why doesn't println! work in Rust unit tests?
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@Nashenas, the option is called nocapture, not no-capture.
– Vladimir Matveev
Jul 16 '15 at 5:21
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How do I get Flask to run on port 80?
...roxy HTTP traffic through apache2 to Flask.
This way, apache2 can handle all your static files (which it's very good at - much better than the debug server built into Flask) and act as a reverse proxy for your dynamic content, passing those requests to Flask.
Here's a link to the official documen...
How to count the number of set bits in a 32-bit integer?
...Hamming Weight', 'popcount' or 'sideways addition'.
The 'best' algorithm really depends on which CPU you are on and what your usage pattern is.
Some CPUs have a single built-in instruction to do it and others have parallel instructions which act on bit vectors. The parallel instructions (like x86's ...
Is a Python dictionary an example of a hash table?
One of the basic data structures in Python is the dictionary, which allows one to record "keys" for looking up "values" of any type. Is this implemented internally as a hash table? If not, what is it?
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Which data type for latitude and longitude?
...y) which can be your lat / long. Occupies 16 bytes: 2 float8 numbers internally.
Or make it two columns of type float (= float8 or double precision). 8 bytes each.
Or real (= float4) if additional precision is not needed. 4 bytes each.
Or even numeric if you need absolute precision. 2 bytes for eac...