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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...
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...
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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Sort a list of tuples by 2nd item (integer value) [duplicate]
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This still works well with Python 3.7.
– jftuga
Oct 30 '18 at 20:44
3
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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...
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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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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OSError: [Errno 2] No such file or directory while using python subprocess in Django
I am trying to run a program to make some system calls inside Python code using subprocess.call() which throws the following error:
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Python - json without whitespaces
...hile indent=None (default) does not in 2.7. All is clearly stated at: docs.python.org/3/library/json.html#json.dump
– Ciro Santilli 郝海东冠状病六四事件法轮功
Jul 28 '16 at 14:01
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