I’m trying to view the frequency of the elements in a 2d array as in the code: Expected result: ({(22, 66): 2, (33, 77): 1, (55, 99): 1}) But I get: Answer Create a list of tuples: (tuples are hashable) Now Counter works: numpys own unique also works
Tag: numpy
Manually entered dataframes which were merged: possibility to sort by date
The below two dataframes df1 and df2 have been manually entered into Python. Then the dataframes were merged into df3. How can I make sure that the final merged dataframe df3 is using the same descending (chronological) order (as for the initial dataframes df1 and df2)(as it is not a case by default)? Thanks …
How to add a row of pixels at the bottom and to the right of an image?
So Im experiencing an issue with a framework that Im working with, where the images sort of get translated by 1 pixel downwards and one pixel to the left (making the pixel data wrong). To counteract this I would like to add a one pixel “padding” then at the bottom & to the left. The script nee…
Slice pandas row of a specific column using numpy boolean
The objective is to slice multiple pandas row of a specific column using a Numpy boolean. The following code should do the task However, I wonder whether the above code can be shortened further, especially these lines Currently, Pandas throw an error if I am to directly using Numpy boolean without converting …
Python Element-wise Multiplication
In MATLAB, I do a calculation using Here, A and B are 1*19-sized matrices. To execute the same code in Python, I am using the following code- Upon running the code, I get the following error- What should I do? Answer MATLAB’s .* is a broadcasting operator. It scalar-extends the * operator to apply to ma…
Load a npz in numpy from bytes
I have a npz file saved from numpy that I can load by using numpy.load(mynpzfile). However, I would like to save this file as a part of a binary file, packed with another file. Something like: However, when reading back the npz I get an error. I have tried load and frombuffer, and both give me an error: fromb…
Keras CNN Model Typevalue errors when using predict method
I am have a keras model that is supposed to take a (150, 150, 1) grayscale image as it’s input and output an array of length 8. Here is my model code: When I try to use the .predict() method, I get this error: I had an ANN (non-CNN) model running earlier that was working fine. When I did some
Not able to read the correct values from a binary file in python
I created and wrote double (data type) values into a binary file. The file does not contain any headers. It is just raw data written into the file using QDataStream in Qt. I am trying to read the values in a python (version 3.6.9) script, however, the data that is read in the python script is not corect. The …
Simulating expectation of continuous random variable
Currently I want to generate some samples to get expectation & variance of it. Given the probability density function: f(x) = {2x, 0 <= x <= 1; 0 otherwise} I already found that E(X) = 2/3, Var(X) = 1/18, my detail solution is from here https://math.stackexchange.com/questions/4430163/simulating-exp…
Create array with random numbers that contains only 1 non zero value in a row
Like in a topic, I want to generate an random array of shape (2x2x2) where each row can contains only one non zero value like not I tried with typical way: Answer I would suggest doing the following to achieve your result. You want an array filled with all zeros, except for one element in each row. So create …