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How to add an extra column to a NumPy array
...np.random.rand(N,N)
b = np.zeros((N,N+1))
b[:,:-1] = a
And timings:
In [23]: N = 10
In [24]: a = np.random.rand(N,N)
In [25]: %timeit b = np.hstack((a,np.zeros((a.shape[0],1))))
10000 loops, best of 3: 19.6 us per loop
In [27]: %timeit b = np.zeros((a.shape[0],a.shape[1]+1)); b[:,:-1] = a
1000...
Get column index from column name in python pandas
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Sure, you can use .get_loc():
In [45]: df = DataFrame({"pear": [1,2,3], "apple": [2,3,4], "orange": [3,4,5]})
In [46]: df.columns
Out[46]: Index([apple, orange, pear], dtype=object)
In [47]: df.columns.get_loc("pear")
Out[47]: 2
although to be honest I don't often need this myself. Usu...
How do I use floating-point division in bash?
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248
You can't. bash only does integers; you must delegate to a tool such as bc.
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How to find the size of localStorage
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226
Execute this snippet in JavaScript console (one line version):
var _lsTotal=0,_xLen,_x;for(_x ...
How do I create a list of random numbers without duplicates?
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edited Apr 2 '18 at 12:59
nbro
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Backporting Python 3 open(encoding=“utf-8”) to Python 2
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1. To get an encoding parameter in Python 2:
If you only need to support Python 2.6 and 2.7 you can use io.open instead of open. io is the new io subsystem for Python 3, and it exists in Python 2,6 ans 2.7 as well. Please be aware that in Python 2.6 (as well as 3.0) ...
Is there a way to measure how sorted a list is?
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142
You can simply count the number of inversions in the list.
Inversion
An inversion in a sequence ...
Using Python String Formatting with Lists
I construct a string s in Python 2.6.5 which will have a varying number of %s tokens, which match the number of entries in list x . I need to write out a formatted string. The following doesn't work, but indicates what I'm trying to do. In this example, there are three %s tokens and the list ...
Query EC2 tags from within instance
Amazon recently added the wonderful feature of tagging EC2 instances with key-value pairs to make management of large numbers of VMs a bit easier.
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How to convert a Binary String to a base 10 integer in Java
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271
You need to specify the radix. There's an overload of Integer#parseInt() which allows you to.
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