Tag: numpy

Python, crop an image to extract a single side of it

I have an image and the vertexs of each sides of it, meaning that, if we see each side as a segment (A,B) i have both the A and B point coordinates. Now i would like to crop the image so that i have only one segment of the image (which is the side), for example That’s just one side

Grouping two variables based on third variable bins in python

numpy pandas python

My intension is to group two variables pairs falling within a third variable’s bin interval. such as: So that I can fetch a XY pair for a particular bin range of third variable, e.g., bin of 25-50 For the same, I tried to sort the “Z” variable and accordingly “X” and “Y” variables, with Z, Y, X = zip(*sorted(zip(Z,Y,X))), that

Select a string which has given value on a particular position

numpy python

I have a ndarray which looks like this example: I need to pick values from the second column, whose corresponding values in the first column matches particular criteria. Example criteria: second and third position of the string (in first column) are equal to zero. If this is true, take a copy of the corresponding values in the second column and

IndexError: shape mismatch: indexing arrays could not be broadcast together with shapes (2,) (3,)

arrays numpy numpy-indexing numpy-ndarray python

I have an np.ndarray of shape (5, 5, 2, 2, 2, 10, 8) named table. I can succesfully slice it like this: But for some reason when I try to specify three values for dimension 5 (of length 10) like this: I get: The same is for: This does not happen with: which output the correct result. I tried to

Binomial distributions (Bernoulli trials) with different probabilities

bernoulli-probability numpy probability python

I want to speed up the code below – namely the for loop. Is there a way to do it in numpy? More explanations – I want to generate N sequences of Bernoulli trials (ie. 0s and 1s, called throws) where each sequence has a mean (probability p) given by values in another array (mu_throws). This can be sampled from

3d numpy array perform operation along column i only

arrays numpy numpy-ndarray python

I have a 3d numpy array like this (as an example) I want to apply the following operations only to elements within the column with index 1 in the inner dimension. The elements are [-2,6,10,14] for the example above. The operations would be: Can someone help me? I have looked into several NumPy methods but can’t seem to adapt to

How to get NumPy array of n last/first Trues in each row

numpy python

I have a broadcasted array, which is sorted rowly, and a masked array. I want to get the last n elements (or the first n ones) of each row which are True i.e.: Do we have to split the array (using np.cumsum(np.sum(mask, axis=1))), pad and …? What will be the best way to do this just with NumPy? Answer Using

Find boundary points of xy coordinates

coordinates numpy python

I have a text file with xy-coordinates called xy.txt. I read the file using and I can plot the points with Visually the data looks as follows: I want to retrieve the xy-coordinates of the points that form the boundary of the shape. Answers on similar questions suggest to use Concave Hull. With the help of this blog I write

python iterate over arrays matrices

arrays matrix numpy python

I am trying to create a new matrix(array) where I have been scouring the documentation in numpy but can’t find a function to satisfy this. Answer You’re looking for numpy.matmul. You’ll need to make the vectors have two dimensions (with a size of one in one of the dimensions). For example:

subtracting time intervals from column dates in dataframes Pandas Python

datetime numpy pandas python python-3.x

How would I be able to subtract 1 second and 1 minute and 1 month from data[‘date’] column? Answer Your date column is of type string. Convert it to pd.Timestamp and you can use pd.DateOffset: