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What is /dev/null 2>&1?
...v/null has the same net effect. I usually just use > for that reason.)
2>&1 redirects standard error (2) to standard output (1), which then discards it as well since standard output has already been redirected.
sh...
How can I plot with 2 different y-axes?
...that each set of points has its own (different) y-axis (i.e., in positions 2 and 4 on the figure) but the points appear superimposed on the same figure.
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How can I get nth element from a list?
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Look here, the operator used is !!.
I.e. [1,2,3]!!1 gives you 2, since lists are 0-indexed.
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Can I get JSON to load into an OrderedDict?
...ecoder(object_pairs_hook=collections.OrderedDict).decode('{"foo":1, "bar": 2}')
OrderedDict([('foo', 1), ('bar', 2)])
>>>
You can pass this parameter to json.loads (if you don't need a Decoder instance for other purposes) like so:
>>> import json
>>> from collections i...
How do I compute derivative using Numpy?
...d choice.
Here is an example using SymPy
In [1]: from sympy import *
In [2]: import numpy as np
In [3]: x = Symbol('x')
In [4]: y = x**2 + 1
In [5]: yprime = y.diff(x)
In [6]: yprime
Out[6]: 2⋅x
In [7]: f = lambdify(x, yprime, 'numpy')
In [8]: f(np.ones(5))
Out[8]: [ 2. 2. 2. 2. 2.]
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~x + ~y == ~(x + y) is always false?
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237
Assume for the sake of contradiction that there exists some x and some y (mod 2n) such that
~...
How to avoid overflow in expr. A * B - C * D
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120
This seems too trivial I guess.
But A*B is the one that could overflow.
You could do the follo...
How to join two sets in one line without using “|”
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320
You can use union method for sets: set.union(other_set)
Note that it returns a new set i.e it ...
Version of Apache installed on a Debian machine
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Try apachectl -V:
$ apachectl -V
Server version: Apache/2.2.9 (Unix)
Server built: Sep 18 2008 21:54:05
Server's Module Magic Number: 20051115:15
Server loaded: APR 1.2.7, APR-Util 1.2.7
Compiled using: APR 1.2.7, APR-Util 1.2.7
... etc ...
If it does not work for you, run th...