I have a NumPy array ‘boolarr’ of boolean type. I want to count the number of elements whose values are True. Is there a NumPy or Python routine dedicated for this task? Or, do I need to iterate over the elements in my script? 6 Answers 6
I’m taking some university classes and have been given an ‘instructional account’, which is a school account I can ssh into to do work. I want to run my computationally intensive Numpy, matplotlib, scipy code on that machine, but I cannot install these modules because I am not a system administrator. How can I do … Read more
I have a simple problem, but I cannot find a good solution to it. I want to take a NumPy 2D array which represents a grayscale image, and convert it to an RGB PIL image while applying some of the matplotlib colormaps. I can get a reasonable PNG output by using the pyplot.figure.figimage command: dpi … Read more
I have a numpy_array. Something like [ a b c ]. And then I want to concatenate it with another NumPy array (just like we create a list of lists). How do we create a NumPy array containing NumPy arrays? I tried to do the following without any luck >>> M = np.array([]) >>> M … Read more
I have a column in python pandas DataFrame that has boolean True/False values, but for further calculations I need 1/0 representation. Is there a quick pandas/numpy way to do that? 9 Answers 9
I notice that In [30]: np.mean([1, 2, 3]) Out[30]: 2.0 In [31]: np.average([1, 2, 3]) Out[31]: 2.0 However, there should be some differences, since after all they are two different functions. What are the differences between them? 5 Answers 5
How can I check whether a numpy array is empty or not? I used the following code, but this fails if the array contains a zero. if not self.Definition.all(): Is this the solution? if self.Definition == array([]): 4 Answers 4
How do I take multiple lists and put them as different columns in a python dataframe? I tried this solution but had some trouble. Attempt 1: Have three lists, and zip them together and use that res = zip(lst1,lst2,lst3) Yields just one column Attempt 2: percentile_list = pd.DataFrame({‘lst1Tite’ : [lst1], ‘lst2Tite’ : [lst2], ‘lst3Tite’ : … Read more
How do I convert a simple list of lists into a numpy array? The rows are individual sublists and each row contains the elements in the sublist. 8 Answers 8
I need to find unique rows in a numpy.array. For example: >>> a # I have array([[1, 1, 1, 0, 0, 0], [0, 1, 1, 1, 0, 0], [0, 1, 1, 1, 0, 0], [1, 1, 1, 0, 0, 0], [1, 1, 1, 1, 1, 0]]) >>> new_a # I want to get to array([[1, … Read more
