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How to apply a function to two columns of Pandas dataframe
...s Series object, and then index the Series to get the values needed.
In [49]: df
Out[49]:
0 1
0 1.000000 0.000000
1 -0.494375 0.570994
2 1.000000 0.000000
3 1.876360 -0.229738
4 1.000000 0.000000
In [50]: def f(x):
....: return x[0] + x[1]
....:
In [51]:...
What is the purpose of the single underscore “_” variable in Python?
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edited Jul 4 at 18:54
user5994461
2,3841414 silver badges3131 bronze badges
answered May ...
Preserving signatures of decorated functions
... """Computes x*y + 2*z"""
return x*y + 2*z
print funny_function("3", 4.0, z="5")
# 22
help(funny_function)
# Help on function funny_function in module __main__:
#
# funny_function(x, y, z=3)
# Computes x*y + 2*z
Python 3.4+
functools.wraps() from stdlib preserves signatures since Py...
Determining 32 vs 64 bit in C++
...r a way to reliably determine whether C++ code is being compiled in 32 vs 64 bit. We've come up with what we think is a reasonable solution using macros, but was curious to know if people could think of cases where this might fail or if there is a better way to do this. Please note we are trying to ...
Format date and time in a Windows batch script
...ecs:~0,1%" == " " set secs=0%secs:~1,1%
echo secs=%secs%
set year=%date:~-4%
echo year=%year%
:: On WIN2008R2 e.g. I needed to make your 'set month=%date:~3,2%' like below ::otherwise 00 appears for MONTH
set month=%date:~4,2%
if "%month:~0,1%" == " " set month=0%month:~1,1%
echo month=%month%
s...
Multi-line string with extra space (preserved indentation)
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answered May 29 '14 at 9:37
new-kidnew-kid
7,39522 gold badges1111 silver badges1616 bronze badges
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Import a file from a subdirectory?
...
Take a look at the Packages documentation (Section 6.4) here: http://docs.python.org/tutorial/modules.html
In short, you need to put a blank file named
__init__.py
in the "lib" directory.
share
...
Approximate cost to access various caches and main memory?
... [Pg. 22]
local L1 CACHE hit, ~4 cycles ( 2.1 - 1.2 ns )
local L2 CACHE hit, ~10 cycles ( 5.3 - 3.0 ns )
local L3 CACHE hit, line unshared ~40 cycles ( 21.4 - 12.0 ns )
local L3 CACHE hit, shared line in ...
How do the likely/unlikely macros in the Linux kernel work and what is their benefit?
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edited Mar 4 '18 at 18:37
jww
1
answered Sep 20 '08 at 23:09
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Unmangling the result of std::type_info::name
...;cxxabi.h>
std::string demangle(const char* name) {
int status = -4; // some arbitrary value to eliminate the compiler warning
// enable c++11 by passing the flag -std=c++11 to g++
std::unique_ptr<char, void(*)(void*)> res {
abi::__cxa_demangle(name, NULL, NULL, &...