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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...
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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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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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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Python: split a list based on a condition?
...ramming (Haskell), or functional style (LINQ) is raised, we start to smell Python for its age - [x for x in blah if ...] - verbose, lambda is clumsy and limited... It feels like driving the coolest car from 1995 today. Not the same as back then.
– Tomasz Gandor
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Why do you have to call .items() when iterating over a dictionary in Python?
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For every python container C, the expectation is that
for item in C:
assert item in C
will pass just fine -- wouldn't you find it astonishing if one sense of in (the loop clause) had a completely different meaning from the other...
Python list directory, subdirectory, and files
...nd not root in the concatenation, since using root would be incorrect.
In Python 3.4, the pathlib module was added for easier path manipulations. So the equivalent to os.path.join would be:
pathlib.PurePath(path, name)
The advantage of pathlib is that you can use a variety of useful methods on pat...