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Why doesn't c++ have &&= or ||= for booleans?
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3 Answers
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Why does Math.round(0.49999999999999994) return 1?
... pathological case.2 Java 7 no longer mandates this broken implementation.3
The problem
0.5+0.49999999999999994 is exactly 1 in double precision:
static void print(double d) {
System.out.printf("%016x\n", Double.doubleToLongBits(d));
}
public static void main(String args[]) {
double a =...
How to check BLAS/LAPACK linkage in NumPy and SciPy?
...rgs = ['-Wl,-framework', '-Wl,Accelerate']
extra_compile_args = ['-msse3']
define_macros = [('NO_ATLAS_INFO', 3)]
blas_opt_info:
extra_link_args = ['-Wl,-framework', '-Wl,Accelerate']
extra_compile_args = ['-msse3', '-I/System/Library/Frameworks/vecLib.framework/Headers']
define_...
Transpose/Unzip Function (inverse of zip)?
... use the special * operator.
>>> zip(*[('a', 1), ('b', 2), ('c', 3), ('d', 4)])
[('a', 'b', 'c', 'd'), (1, 2, 3, 4)]
The way this works is by calling zip with the arguments:
zip(('a', 1), ('b', 2), ('c', 3), ('d', 4))
… except the arguments are passed to zip directly (after being co...
Finding three elements in an array whose sum is closest to a given number
...P: Given an array A of n integers and a target value S, does there exist a 3-tuple from A that sums to S?
modified problem P': Given an array A of n integers, does there exist a 3-tuple from A that sums to zero?
Notice that you can go from this version of the problem P' from P by subtracting ...
How to trace the path in a Breadth-First Search?
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# graph is in adjacent list representation
graph = {
'1': ['2', '3', '4'],
'2': ['5', '6'],
'5': ['9', '10'],
'4': ['7', '8'],
'7': ['11', '12']
}
def bfs(graph, start, end):
# maintain a queue of paths
queue = []
# push the first path i...
Implementing slicing in __getitem__
...m__(self, val):
... print val
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>>> c = C()
>>> c[3]
3
>>> c[3:4]
slice(3, 4, None)
>>> c[3:4:-2]
slice(3, 4, -2)
>>> c[():1j:'a']
slice((), 1j, 'a')
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How to configure PostgreSQL to accept all incoming connections
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edited Oct 23 '18 at 19:31
Basil Bourque
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Python Dictionary Comprehension
...t; d = {n: n**2 for n in range(5)}
>>> print d
{0: 0, 1: 1, 2: 4, 3: 9, 4: 16}
If you want to set them all to True:
>>> d = {n: True for n in range(5)}
>>> print d
{0: True, 1: True, 2: True, 3: True, 4: True}
What you seem to be asking for is a way to set multiple ke...