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How to install packages offline?
...on 3. you can create python 3 virtualenv with this command.
virtualenv -p python3 envname
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How to remove a key from a Python dictionary?
...])
[1, 3, None] # pop returns
>>> myDict
{'b': 2, 'd': 4}
or in python3, you must use a list comprehension instead:
[myDict.pop(x, None) for x in ['a', 'c', 'e']]
It works. And 'e' did not cause an error, even though myDict did not have an 'e' key.
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Counting the Number of keywords in a dictionary in python
...Some modifications were made on posted answer UnderWaterKremlin to make it python3 proof. A surprising result below as answer.
System specs:
python =3.7.4,
conda = 4.8.0
3.6Ghz, 8 core, 16gb.
import timeit
d = {x: x**2 for x in range(1000)}
#print (d)
print (len(d))
# 1000
print (len(d.keys()...
what is the difference between 'transform' and 'fit_transform' in sklearn
...ea2aff> in <module>()
----> 1 pc2.transform(X)
/usr/local/lib/python3.4/dist-packages/sklearn/decomposition/pca.py in transform(self, X, y)
714 # XXX remove scipy.sparse support here in 0.16
715 X = atleast2d_or_csr(X)
--> 716 if self.mean_ is not None...
Sending HTML email using Python
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for python3, improve @taltman 's answer:
use email.message.EmailMessage instead of email.message.Message to construct email.
use email.set_content func, assign subtype='html' argument. instead of low level func set_payload and ...
UnicodeEncodeError: 'charmap' codec can't encode - character maps to , print function [du
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@MartijnPieters if you click the link then you see Python3.6 recommendation.
– jfs
Jan 13 '17 at 17:52
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How to convert list of tuples to multiple lists?
...ppend is 3x - 4x faster than zip! The test script is here:
#!/usr/bin/env python3
import time
N = 2000000
xs = list(range(1, N))
ys = list(range(N+1, N*2))
zs = list(zip(xs, ys))
t1 = time.time()
xs_, ys_ = zip(*zs)
print(len(xs_), len(ys_))
t2 = time.time()
xs_, ys_ = [], []
for x, y in zs:
...
multiprocessing: How do I share a dict among multiple processes?
... that can be converted to dict
pprint.pprint(dict(d))
Output:
$ python3 mul.py
{22562: 'Hi, I was written by process 22562',
22563: 'Hi, I was written by process 22563',
22564: 'Hi, I was written by process 22564',
22565: 'Hi, I was written by process 22565',
22566: 'Hi, I was writte...
What does -> mean in Python function definitions?
...cause most python libraries still aim to be compatible with python2.x. As python3.x begins to become more standard, we might see more of these things popping up here and there...
– mgilson
Jan 17 '13 at 14:15
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Python Sets vs Lists
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@RyneWang this is true, but only for Python3. In Python2 range returns a normal list (that's why exists horrible things like xrange)
– Manoel Vilela
Dec 11 '18 at 17:55
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