Suppose you have an array: a = [ 0,1,0] [-1,2,1] [3,-4,2] And lets say you add 20 to everything b = [ 20, 21, 20] [ 19, 22, 21] [ 23, 16, 22] Now lets say I want to add the resulting b to the original array a but only in cases where a < 0 i.e at the index
Tag: arrays
What does axis = 0 do in Numpy’s sum function?
I am learning Python, and have encountered numpy.sum. It has an optional parameter axis. This parameter is used to get either column-wise summation or row-wise summation. When axis = 0 we imply to sum it over columns only. For example, This snippet of code produces output: array([5, 7, 9]), fine. But if I do: I get result: 6, why is
Array of tuples necessary for generate_from_frequencies method in Python wordcloud
I am trying to make a word cloud in Python from the significance of strings and their corresponding data values in an Excel document. The generate_from_frequencies method takes a frequencies parameter which the docs say is supposed to take an array of tuples. Partial code from wordcloud source code: I tried using a regular list, then I tried a ndarray
How to create a numpy array from a pydub AudioSegment?
I’m aware of the following question: How to create a pydub AudioSegment using an numpy array? My question is the right opposite. If I have a pydub AudioSegment how can I convert it to a numpy array? I would like to use scipy filters and so on. It is not very clear to me what is the internal structure of
Get the highest value of a specific field from an API reponse in Python
I make a GET to a API I got this back I have Goal is to get the highest account id out of it. Answer Usually we like to see what OPs try themselves, this is pretty much straightforward.
Why are Python’s arrays slow?
I expected array.array to be faster than lists, as arrays seem to be unboxed. However, I get the following result: What could be the cause of such a difference? Answer The storage is “unboxed”, but every time you access an element Python has to “box” it (embed it in a regular Python object) in order to do anything with it.
python how to pad numpy array with zeros
I want to know how I can pad a 2D numpy array with zeros using python 2.6.6 with numpy version 1.5.0. But these are my limitations. Therefore I cannot use np.pad. For example, I want to pad a with zeros such that its shape matches b. The reason why I want to do this is so I can do: such
How can a string representation of a NumPy array be converted to a NumPy array?
The function numpy.array_repr can be used to create a string representation of a NumPy array. How can a string representation of a NumPy array be converted to a NumPy array? Let’s say the string representation is as follows: How could this be converted to a NumPy array? Answer eval is the easiest, probably. It evaluates a given string as if
How to create a numpy array of lists?
I want to create a numpy array in which each element must be a list, so later I can append new elements to each. I have looked on google and here on stack overflow already, yet it seems nowhere to be found. Main issue is that numpy assumes your list must become an array, but that is not what I
Viewing .npy images
How can I view images stored with a .npy extension and save my own files in that format? Answer .npy is the file extension for numpy arrays – you can read them using numpy.load: One of the easiest ways to view them is using matplotlib’s imshow function: You could also use PIL or pillow: These functions aren’t part of the