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Fast permutation -> number -> permutation mapping algorithms
...ake of an example, let's say, 7 elements, 1234567. I know there are 7! = 5040 permutations possible of these 7 elements.
1...
What is the difference between 0.0.0.0, 127.0.0.1 and localhost?
...ekyll and Vagrant on my mac. I found that Jekyll server will bind to 0.0.0.0:4000 instead of 127.0.0.1:4000 . Also gem server will bind to this address by default. I can still visit it via http://localhost:port . But for Jekyll , it seems that the default setting (e.g. 0.0.0.0:4000) req...
Apply pandas function to column to create multiple new columns?
...,
left_index=True, right_index=True)
textcol feature1 feature2
0 0.772692 1.772692 -0.227308
1 0.857210 1.857210 -0.142790
2 0.065639 1.065639 -0.934361
3 0.819160 1.819160 -0.180840
4 0.088212 1.088212 -0.911788
EDIT:
Please be aware of the huge memory consumption and low sp...
Looping in a spiral
...
Here's my solution (in Python):
def spiral(X, Y):
x = y = 0
dx = 0
dy = -1
for i in range(max(X, Y)**2):
if (-X/2 < x <= X/2) and (-Y/2 < y <= Y/2):
print (x, y)
# DO STUFF...
if x == y or (x < 0 and x == -y) or (x &...
What are the differences between json and simplejson Python modules?
...
wim
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answered Apr 3 '09 at 6:59
Devin JeanpierreDe...
Reference — What does this symbol mean in PHP?
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How do you detect where two line segments intersect? [closed]
...th s, getting
(p + t r) × s = (q + u s) × s
And since s × s = 0, this means
t (r × s) = (q − p) × s
And therefore, solving for t:
t = (q − p) × s / (r × s)
In the same way, we can solve for u:
(p + t r) × r = (q + u s) × r
u (s × r) = (p − q) × r
...
How to drop rows of Pandas DataFrame whose value in a certain column is NaN
...
AMC
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answered Nov 16 '12 at 9:34
eumiroeumiro
1...
Syntax for creating a two-dimensional array
...
Try the following:
int[][] multi = new int[5][10];
... which is a short hand for something like this:
int[][] multi = new int[5][];
multi[0] = new int[10];
multi[1] = new int[10];
multi[2] = new int[10];
multi[3] = new int[10];
multi[4] = new int[10];
Note that every...
How to use glOrtho() in OpenGL?
...window is resized:
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0f, windowWidth, windowHeight, 0.0f, 0.0f, 1.0f);
This will remap the OpenGL coordinates into the equivalent pixel values (X going from 0 to windowWidth and Y going from 0 to windowHeight). Note that I've flipped the Y va...