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What's the common practice for enums in Python? [duplicate]
...
class Materials:
Shaded, Shiny, Transparent, Matte = range(4)
>>> print Materials.Matte
3
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How can I add reflection to a C++ application?
...ow to iterate over the fields we use the visitor pattern. We create an MPL range from 0 to the number of fields, and access the field data at that index. Then it passes the field data on to the user-provided visitor:
struct field_visitor
{
template<class C, class Visitor, class I>
voi...
Python initializing a list of lists [duplicate]
...instance.
To make a list of 3 different lists, do this:
x = [[] for i in range(3)]
This gives you 3 separate instances of [], which is what you want
[[]]*n is similar to
l = []
x = []
for i in range(n):
x.append(l)
While [[] for i in range(3)] is similar to:
x = []
for i in range(n):
...
Changing specific text's color using NSMutableAttributedString in Swift
...g e.g.
var main_string = "Hello World"
var string_to_color = "World"
var range = (main_string as NSString).rangeOfString(string_to_color)
Then you convert to attributed string and use 'add attribute' with NSForegroundColorAttributeName:
var attributedString = NSMutableAttributedString(string:ma...
How do I add the contents of an iterable to a set?
...You can add elements of a list to a set like this:
>>> foo = set(range(0, 4))
>>> foo
set([0, 1, 2, 3])
>>> foo.update(range(2, 6))
>>> foo
set([0, 1, 2, 3, 4, 5])
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Cartesian product of x and y array points into single array of 2D points
... cartesian_product_recursive(arrays[1:], out=out[0:m,1:])
for j in range(1, arrays[0].size):
out[j*m:(j+1)*m,1:] = out[0:m,1:]
return out
def cartesian_product_itertools(*arrays):
return numpy.array(list(itertools.product(*arrays)))
### Test code ###
name_func = [('rep...
How do you iterate through every file/directory recursively in standard C++?
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From C++17 onward, the <filesystem> header, and range-for, you can simply do this:
#include <filesystem>
using recursive_directory_iterator = std::filesystem::recursive_directory_iterator;
...
for (const auto& dirEntry : recursive_directory_iterator(myPath))
...
Get difference between two lists
...emp1 if x not in s]
Performance test
import timeit
init = 'temp1 = list(range(100)); temp2 = [i * 2 for i in range(50)]'
print timeit.timeit('list(set(temp1) - set(temp2))', init, number = 100000)
print timeit.timeit('s = set(temp2);[x for x in temp1 if x not in s]', init, number = 100000)
print ...
RE error: illegal byte sequence on Mac OS X
...ly recognize basic English letters as letters (the ones in the 7-bit ASCII range), so that foreign chars. will not be treated as letters, causing, for instance, upper-/lowercase conversions to fail.
Again, this may be fine if you needn't match multibyte-encoded characters such as é, and simply wan...
Convert Long into Integer
...situations, you might run into overflows (because a Long can store a wider range than an Integer).
Java 8 has a helper method that checks for overflow (you get an exception in that case):
Integer i = theLong == null ? null : Math.toIntExact(theLong);
...