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Should I implement __ne__ in terms of __eq__ in Python?
I have a class where I want to override the __eq__ method. It seems to make sense that I should override the __ne__ method as well, but does it make sense to implement __ne__ in terms of __eq__ as such?
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How to access the ith column of a NumPy multidimensional array?
...0,2]] = something would modify test, and not create another array. But copy_test = test[:, [0,2]] does in fact create a copy as you say.
– Akavall
Apr 11 '14 at 16:19
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Passing a 2D array to a C++ function
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Fixed Size
1. Pass by reference
template <size_t rows, size_t cols>
void process_2d_array_template(int (&array)[rows][cols])
{
std::cout << __func__ << std::endl;
for (size_t i = 0; i < rows; ++i)
{
std::cout << i << ...
Python - Create a list with initial capacity
...ux
Perhaps you could avoid the list by using a generator instead:
def my_things():
while foo:
#baz
yield bar
#qux
for thing in my_things():
# do something with thing
This way, the list isn't every stored all in memory at all, merely generated as needed.
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Logical operators for boolean indexing in Pandas
...l-and since only x or y can be returned. In contrast, x & y triggers x.__and__(y) and the __and__ method can be defined to return anything we like.
– unutbu
Apr 15 '16 at 22:58
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Importing from builtin library when module with same name exists
Situation:
- There is a module in my project_folder called calendar
- I would like to use the built-in Calendar class from the Python libraries
- When I use from calendar import Calendar it complains because it's trying to load from my module.
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In Python, if I return inside a “with” block, will the file still close?
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@RikPoggi os._exit is sometimes used - it exits the Python process without calling cleanup handlers.
– Acumenus
Oct 8 '16 at 6:25
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In Python, how do I read the exif data for an image?
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You can use the _getexif() protected method of a PIL Image.
import PIL.Image
img = PIL.Image.open('img.jpg')
exif_data = img._getexif()
This should give you a dictionary indexed by EXIF numeric tags. If you want the dictionary indexed by t...
Why does GCC generate 15-20% faster code if I optimize for size instead of speed?
...ssembly from gcc-4.6.4 -Os (executes in 0.709 secs):
00000000004004d2 <_ZL3addRKiS0_.isra.0>:
4004d2: 8d 04 37 lea eax,[rdi+rsi*1]
4004d5: c3 ret
00000000004004d6 <_ZL4workii>:
4004d6: 41 55 push r13
4...
What is the most efficient string concatenation method in python?
...iven the test case from mkoistinen's answer, having strings
domain = 'some_really_long_example.com'
lang = 'en'
path = 'some/really/long/path/'
The contenders are
f'http://{domain}/{lang}/{path}' - 0.151 µs
'http://%s/%s/%s' % (domain, lang, path) - 0.321 µs
'http://' + domain + '/' + lang ...