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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:
...
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.
...
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...
UnicodeEncodeError: 'charmap' codec can't encode - character maps to , print function [du
...
@MartijnPieters if you click the link then you see Python3.6 recommendation.
– jfs
Jan 13 '17 at 17:52
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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...
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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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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Getting the name of a variable as a string
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On python3, this function will get the outer most name in the stack:
import inspect
def retrieve_name(var):
"""
Gets the name of var. Does it from the out most frame inner-wards.
:param var: variable t...
Python - List of unique dictionaries
... 34, 'id': 1, 'name': 'john'}, {'age': 30, 'id': 2, 'name': 'hanna'}]
In Python3
>>> L=[
... {'id':1,'name':'john', 'age':34},
... {'id':1,'name':'john', 'age':34},
... {'id':2,'name':'hanna', 'age':30},
... ]
>>> list({v['id']:v for v in L}.values())
[{'age': 34, 'id': 1, 'nam...
Find the most common element in a list
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This breaks on Python3 if your list has different types.
– AlexLordThorsen
Feb 24 '16 at 22:47
2
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