Numpy

Numpy is a package used to conduct data analysis in Python. For Dash, numpy arrays are useful as input for Plotly and Dash objects (Dash is built by Plotly)

First install pandas and numpy

pip install numpy

Import numpy

import numpy as np

Arrays in Numpy

Convert list to array
mylist = [1,2,3,4]
arr = np.array(mylist)

Differences with Lists

• + in arrays do element-wise addition, versus concatenation in lists
• • in arrays do element-wise multiplication, versus duplication in lists
• ** in arrays do element-wise squaring; this does not work in lists

Math operations

np.sum() gives sum of elements in array
np.dot() gives dot product of two arrays
np.sqrt() gives square root of an array
np.mean() gives mean of array
np.var() gives variance of array