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What is the difference between & and && in Java?
...g if the first operand evaluates to false since the result will be false
(x != 0) & (1/x > 1) <-- this means evaluate (x != 0) then evaluate (1/x > 1) then do the &. the problem is that for x=0 this will throw an exception.
(x != 0) && (1/x > 1) <-- this means evalua...
C++ Tuple vs Struct
...rst start with a default struct and a tuple.
struct StructData {
int X;
int Y;
double Cost;
std::string Label;
bool operator==(const StructData &rhs) {
return std::tie(X,Y,Cost, Label) == std::tie(rhs.X, rhs.Y, rhs.Cost, rhs.Label);
}
bool operator<(con...
How to do multiple arguments to map function where one remains the same in python?
...
One option is a list comprehension:
[add(x, 2) for x in [1, 2, 3]]
More options:
a = [1, 2, 3]
import functools
map(functools.partial(add, y=2), a)
import itertools
map(add, a, itertools.repeat(2, len(a)))
...
How to calculate an angle from three points? [closed]
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If you mean the angle that P1 is the vertex of then using the Law of Cosines should work:
arccos((P122
+ P132 - P232) / (2 *
P12 * P13))
where P12 is the length of the segment from P1 to P2, calculated by
sqrt((P1x -
P2x)2 +
(P1y -
P2y)2)
...
Finding local maxima/minima with Numpy in a 1D numpy array
Can you suggest a module function from numpy/scipy that can find local maxima/minima in a 1D numpy array? Obviously the simplest approach ever is to have a look at the nearest neighbours, but I would like to have an accepted solution that is part of the numpy distro.
...
What is the difference between an expression and a statement in Python?
In Python, what is the difference between expressions and statements?
14 Answers
14
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Why are Python lambdas useful? [closed]
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Are you talking about lambda functions? Like
lambda x: x**2 + 2*x - 5
Those things are actually quite useful. Python supports a style of programming called functional programming where you can pass functions to other functions to do stuff. Example:
mult3 = filter(lambda x:...
cocktail party algorithm SVD implementation … in one line of code?
...ully it'll help someone.
You need 2 audio recordings. You can get audio examples from http://research.ics.aalto.fi/ica/cocktail/cocktail_en.cgi.
reference for implementation is http://www.cs.nyu.edu/~roweis/kica.html
ok, here's code -
[x1, Fs1] = audioread('mix1.wav');
[x2, Fs2] = audioread('m...
How to break out from a ruby block?
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Use the keyword next. If you do not want to continue to the next item, use break.
When next is used within a block, it causes the block to exit immediately, returning control to the iterator method, which may then begin a new iteration by inv...
How to get the first column of a pandas DataFrame as a Series?
...
>>> import pandas as pd
>>> df = pd.DataFrame({'x' : [1, 2, 3, 4], 'y' : [4, 5, 6, 7]})
>>> df
x y
0 1 4
1 2 5
2 3 6
3 4 7
>>> s = df.ix[:,0]
>>> type(s)
<class 'pandas.core.series.Series'>
>>>
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