How to get the index of a maximum element in a NumPy array along one axis
I have a 2 dimensional NumPy array. I know how to get the maximum values over axes:
numpy
How do I convert a numpy array to (and display) an image?
I have created an array thusly:
best way to preserve numpy arrays on disk
I am looking for a fast way to preserve large numpy arrays. I want to save them to the disk in a binary format, then read them back into memory relatively fastly. cPickle is not fast enough, unfortunately.
Compute a confidence interval from sample data
I have sample data which I would like to compute a confidence interval for, assuming a normal distribution.
Pandas Timedelta in Days
I have a dataframe in pandas called ‘munged_data’ with two columns ‘entry_date’ and ‘dob’ which i have converted to Timestamps using pd.to_timestamp.I am trying to figure out how to calculate ages of people based on the time difference between ‘entry_date’ and ‘dob’ and to do this i need to get the difference in days between the two columns ( so that i can then do somehting like round(days/365.25). I do not seem to be able to find a way to do this using a vectorized operation. When I do munged_data.entry_date-munged_data.dob i get the following :
Share Large, Read-Only Numpy Array Between Multiprocessing Processes
I have a 60GB SciPy Array (Matrix) I must share 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 dtypes to ctypes. Now, numpy-sharedmem seems to be the way to go, but I’ve yet to see a good reference example. I don’t need any kind of locks, since the array (actually a matrix) will be read-only. Now, due to its size, I’d like to avoid a copy. It sounds like the correct method is to create the only copy of the array as a sharedmem array, and then pass it to the Process objects? A couple of specific questions:
How does NumPy’s transpose() method permute the axes of an array?
By default, reverse the dimensions, otherwise permute the axes according to the values given.
Numpy sum elements in array based on its value
I have unsorted array of indexes:
How can I attach a pyplot function to a figure instance?
Previously, I had a problem with the interference between multiple Matplotlib figures. Finally i got tracked that to an issue that some pyplot functions do not attach to their figure instance but can be rendered in some other figure instances which are created in parallel.
Numpy matrix to array
I am using numpy. I have a matrix with 1 column and N rows and I want to get an array from with N elements.