Numpy passing input array as `out` argument to ufunc Question: Is it generally safe to provide the input array as the optional out argument to a ufunc in numpy, provided the type is correct? For example, I have verified that the following works: >>> import numpy as np >>> arr = np.array([1.2, 3.4, 4.5]) >>> …
Pandas: peculiar performance drop for inplace rename after dropna Question: I have reported this as an issue on pandas issues. In the meanwhile I post this here hoping to save others time, in case they encounter similar issues. Upon profiling a process which needed to be optimized I found that renaming columns NOT inplace improves …
What is the difference between `sorted(list)` vs `list.sort()`? Question: list.sort() sorts the list and replaces the original list, whereas sorted(list) returns a sorted copy of the list, without changing the original list. When is one preferred over the other? Which is more efficient? By how much? Can a list be reverted to the unsorted state …
Numpy modify array in place? Question: I have the following code which is attempting to normalize the values of an m x n array (It will be used as input to a neural network, where m is the number of training examples and n is the number of features). However, when I inspect the array …
Python Math – TypeError: 'NoneType' object is not subscriptable Question: I’m making a small program for math (no particular reason, just kind of wanted to) and I ran into the error “TypeError: ‘NoneType’ object is not subscriptable. I have never before seen this error, so I have no idea what it means. import math print(“The …
