I want to change first column to int in dnarray [[ 1. 6.218 2.974 0. ] [ 2. 32.881 8.66 0. ] [ 3. 38.94 35.843 0. ] [ 4. 8.52 35.679 0. ] [ 5. 52.902 49.538 0. ]] float64 int32 float64 I tried to use deepcopy, but no success. Any help will be good, I didn’t find any
Tag: numpy
Working with 2 arrays to populate a third one in numpy
I am trying to work with two arrays in a certain way in python. Lets say now I have a target array C = [2, 7, 15, 25, 40]. I want to find a output value (say Y) for each element in C (say x) with conditions: If x < A[0] then Y = B[0] If A[i] < x <
how to perform a backwards correlation/convolution in python
I am trying to perform a backwards correlation (at least that’s what I think it’s called) on 2 matrices to get a resultant matrix. Note: backwards convolution works too, because I’m applying this to a CNN. I have the following two matrices: vals: w0: I essentially want to apply a sliding win…
Map pandas dataframe columns to an array
I have a dataframe like this: And an array like: The first element will be for family_id=0 and column “choice_0” = 52 The second element will be for family_id=1 and column “choice_2” = 82 The third element will be for family_id=2 and column “choice_4” = 27 And I will like t…
Pandas: Remove Column Based on Threshold Criteria
I have to solve this problem: Objective: Drops columns most of whose rows missing Inputs: 1. Dataframe df: Pandas dataframe 2. threshold: Determines which columns will be dropped. If threshold is .9, the columns with 90% missing value will be dropped Outputs: 1. Dataframe df with dropped columns (if no column…
Drop rows that contains the data between specific dates
The file contains data by date and time: All I want I want drop rows that contains between these dates and includes the start and end dates: Any Idea? Answer Sample: Use boolean indexing for filter by condition with chain by | for bitwise OR: Or filter by Series.between and invert mask by ~:
Finding the minimum of the N numpy matrices?
I want to find the minimum of N numpy matrices elementwise (but with a twist, read till the end). To show, I create 3 numpy matrices as follows: I except my output d to be: I also need to retain the information from where does the each element in the d matrix is coming from. So if I label a,
Find all coordinates of black / grey pixels in image using python
I’m trying to find a way to read any any .png, .jpg or .tiff, and return the coordinates of all black or grey pixels in that image. I’m thinking of having a certain threshold grey color, and writing out the coordinates of every pixel that is darker than that. I’m not sure how to manage the a…
How to create a Python convolution kernel?
I’m trying to create a convolution kernel, and the middle is going to be 1.5. Unfortunately I keep running in to ideas on how to do that. I’m trying to create something similar to this Answer Since OpenCV uses Numpy to display images, you can simply create a convolution kernel using Numpy. Here…
Is there a fast way to shuffle numpy image in segments?
I want to write a function that can take small images and return a permutation of them, block-wise. Basically I want to turn this: Into this: There was an excellent answer in Is there a function in Python that shuffle data by data blocks? that helped me write a solution. However for ~50,000 28×28 images …