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Find indices of elements equal to zero in a NumPy array
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numpy.where() is my favorite.
>>> x = numpy.array([1,0,2,0,3,0,4,5,6,7,8])
>>> numpy.where(x == 0)[0]
array([1, 3, 5])
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Operation on every pair of element in a list
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233
Check out product() in the itertools module. It does exactly what you describe.
import iterto...
Numpy where function multiple conditions
...e values, then a and b returns b. So saying something like [0,1,2] and [2,3,4] will just give you [2,3,4]. Here it is in action:
In [230]: dists = np.arange(0,10,.5)
In [231]: r = 5
In [232]: dr = 1
In [233]: np.where(dists >= r)
Out[233]: (array([10, 11, 12, 13, 14, 15, 16, 17, 18, 19]),)
I...
How to get all subsets of a set? (powerset)
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137
The Python itertools page has exactly a powerset recipe for this:
from itertools import chain,...
pandas: filter rows of DataFrame with operator chaining
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398
I'm not entirely sure what you want, and your last line of code does not help either, but anyw...
Are tuples more efficient than lists in Python?
...s much faster than assigning a list.
>>> def a():
... x=[1,2,3,4,5]
... y=x[2]
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>>> def b():
... x=(1,2,3,4,5)
... y=x[2]
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>>> import dis
>>> dis.dis(a)
2 0 LOAD_CONST 1 (1)
3 LOAD_CONST ...
How to print a percentage value in python?
...age floating point precision type:
>>> print "{0:.0%}".format(1./3)
33%
If you don't want integer division, you can import Python3's division from __future__:
>>> from __future__ import division
>>> 1 / 3
0.3333333333333333
# The above 33% example would could now be w...
Is it worth using Python's re.compile?
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TriptychTriptych
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How to pad zeroes to a string?
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Strings:
>>> n = '4'
>>> print(n.zfill(3))
004
And for numbers:
>>> n = 4
>>> print(f'{n:03}') # Preferred method, python >= 3.6
004
>>> print('%03d' % n)
004
>>> print(format(n, '03')) # python >= 2.6
004
>>> ...
List comprehension on a nested list?
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332
Here is how you would do this with a nested list comprehension:
[[float(y) for y in x] for x ...