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Is there a built in function for string natural sort?
Using Python 3.x, I have a list of strings for which I would like to perform a natural alphabetical sort.
18 Answers
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Check if a given key already exists in a dictionary and increment it
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You are looking for collections.defaultdict (available for Python 2.5+). This
from collections import defaultdict
my_dict = defaultdict(int)
my_dict[key] += 1
will do what you want.
For regular Python dicts, if there is no value for a given key, you will not get None when access...
Aren't Python strings immutable? Then why does a + “ ” + b work?
My understanding was that Python strings are immutable.
22 Answers
22
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Plotting a list of (x, y) coordinates in python matplotlib
...ve a list of pairs (a, b) that I would like to plot with matplotlib in python as actual x-y coordinates. Currently, it is making two plots, where the index of the list gives the x-coordinate, and the first plot's y values are the a s in the pairs and the second plot's y values are the b s in t...
File I/O in Every Programming Language [closed]
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Python 3
with open('fileio.txt', 'w') as f:
f.write('hello')
with open('fileio.txt', 'a') as f:
f.write('\nworld')
with open('fileio.txt') as f:
s = f.readlines()[1]
print(s)
Clarifications
readlines() returns a...
Pairs from single list
...nd the need to process a list by pairs. I was wondering which would be the pythonic and efficient way to do it, and found this on Google:
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Pass a local file in to URL in Java
...file:/// but a URL with file:/ ..." Is that the case for both Windows and Linux?
– ptntialunrlsd
Jul 13 '15 at 9:19
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ImportError: Cannot import name X
.... This is extremely important in C++, and even if it's not the #1 thing in Python, it's still a really good idea to follow this rule. Never have two classes which know each other, ever. If you need help with creating the structure for your classes, post rest of the code too. How exactly (in terms of...
Create numpy matrix filled with NaNs
...atives a[:] = numpy.nan here and a.fill(numpy.nan) as posted by Blaenk:
$ python -mtimeit "import numpy as np; a = np.empty((100,100));" "a.fill(np.nan)"
10000 loops, best of 3: 54.3 usec per loop
$ python -mtimeit "import numpy as np; a = np.empty((100,100));" "a[:] = np.nan"
10000 loops, best of...
Python string.join(list) on object array rather than string array
In Python, I can do:
4 Answers
4
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