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Get statistics for each group (such as count, mean, etc) using pandas GroupBy?
I have a data frame df and I use several columns from it to groupby :
7 Answers
7
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TCP: can two different sockets share a port?
...lished connection is uniquely identified by the combination of client-side and server-side IP/Port pairs. Multiple connections on the same server can share the same server-side IP/Port pair as long as they are associated with different client-side IP/Port pairs, and the server would be able to hand...
Share Large, Read-Only Numpy Array Between Multiprocessing Processes
... between 5+ multiprocessing Process objects. I've seen numpy-sharedmem and read this discussion on the SciPy list. There seem to be two approaches-- numpy-sharedmem and using a multiprocessing.RawArray() and mapping NumPy dtype s to ctype s. Now, numpy-sharedmem seems to be the way to g...
How can I profile Python code line-by-line?
I've been using cProfile to profile my code, and it's been working great. I also use gprof2dot.py to visualize the results (makes it a little clearer).
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How to determine if a list of polygon points are in clockwise order?
...gth (x2-x1). Notice the sign convention in x. Try this with some triangles and you'll soon see how it works.
– Beta
Jul 27 '09 at 14:20
75
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How to map atan2() to degrees 0-360
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For those not comfortable with this notation, and without the conversion to degrees built in: if(x>0) {radians = x;} else {radians = 2*PI + x;} so we are just adding 2PI to the result if it is less than 0.
– David Doria
Sep 25 '1...
Tricky Google interview question
... = 0; // Index for 5
int x2 = 2 * v[i2]; // Next two candidates
int x5 = 5 * v[i5];
for (int i = 1; i != n; ++i)
{
int m = std::min(x2, x5);
std::cout << m << " ";
v[i] = m;
if (x2 == m)
{
++i2;
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How do I tell Maven to use the latest version of a dependency?
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NOTE:
This answer applies to Maven 2 only! The mentioned LATEST and RELEASE metaversions have been dropped in Maven 3 "for the sake of reproducible builds", over 6 years ago.
Please refer to this Maven 3 compliant solution.
If you always want to use the newest version, Maven has two k...
How dangerous is it to compare floating point values?
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First of all, floating point values are not "random" in their behavior. Exact comparison can and does make sense in plenty of real-world usages. But if you're going to use floating point you need to be aware of how it works. Erring on the side of assuming floating point ...
Finding duplicates in O(n) time and O(1) space
...ns in O(N) time. A swap only occurs if there is an i such that A[i] != i, and each swap sets at least one element such that A[i] == i, where that wasn't true before. This means that the total number of swaps (and thus the total number of executions of the while loop body) is at most N-1.
The seco...