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Append a NumPy array to a NumPy array
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234
In [1]: import numpy as np
In [2]: a = np.array([[1, 2, 3], [4, 5, 6]])
In [3]: b = np.array...
StringIO in Python3
I am using Python 3.2.1 and I can't import the StringIO module. I use
io.StringIO and it works, but I can't use it with numpy 's genfromtxt like this:
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Get the cartesian product of a series of lists?
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itertools.product
Available from Python 2.6.
import itertools
somelists = [
[1, 2, 3],
['a', 'b'],
[4, 5]
]
for element in itertools.product(*somelists):
print(element)
Which is the same as,
for element in itertools.product([1, 2, 3], ['a', 'b'], ...
How to run multiple Python versions on Windows
I had two versions of Python installed on my machine (versions 2.6 and 2.5). I want to run 2.6 for one project and 2.5 for another.
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SVN needs-lock 设置强制只读属性（官方资料） - 环境配置 - 清泛IT论坛，...
... is not available (Windows only):@echo off
set REPOS=%1
set TRANSACTION=%2
set SVNLOOK="c:\Program Files\Subversion\apache2.2\bin\svnlook.exe"
set TEMP=c:\temp
if exist %TEMP%\tempfile%2 del %TEMP%\tempfile%2
for /f "tokens=1,2 usebackq" %%i in (`%SVNLOOK% changed -t %2 %1`)...
“Cloning” row or column vectors
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Here's an elegant, Pythonic way to do it:
>>> array([[1,2,3],]*3)
array([[1, 2, 3],
[1, 2, 3],
[1, 2, 3]])
>>> array([[1,2,3],]*3).transpose()
array([[1, 1, 1],
[2, 2, 2],
[3, 3, 3]])
the problem with [16] seems to be that the transpose has ...
What does ** (double star/asterisk) and * (star/asterisk) do for parameters?
... the following method definitions, what does the * and ** do for param2 ?
22 Answers
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What does -1 mean in numpy reshape?
...inal shape'
numpy allow us to give one of new shape parameter as -1 (eg: (2,-1) or (-1,3) but not (-1, -1)). It simply means that it is an unknown dimension and we want numpy to figure it out. And numpy will figure this by looking at the 'length of the array and remaining dimensions' and making su...
Split data frame string column into multiple columns
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291
Use stringr::str_split_fixed
library(stringr)
str_split_fixed(before$type, "_and_", 2)
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