CODEWITHSUNDEEP
pythonmatrix
Latif Fetahaj
Latif Fetahaj

Reputation: 13

How to bin values in a list into categories

For example, the double values in the first array [1.2,4.6,3.7,11.2,13,5,18.9,0.3,20.0,26.7,1] now I want to create another array based on the first one with states 1, 2 and 3 for every value in the first array that is in the range [0,10) add the value 1 in the second array so the range [0,10) represents state 1 the range [10,20) represents state 2 the range [20,30) represents state 3

so at the end, the second array would look like [1,1,1,2,2,2,1,3,3,1] This is a transition state array that will help to build the transition matrix in python **

Upvotes: 0

Views: 129

Answers (2)

Seleme
Seleme

Reputation: 251

If you do not want to use numpy (see yatu's solution) or want to explicitly see a basic pure Python implementation, check out the below: 

arr = [1.2,4.6,3.7,11.2,13,5,18.9,0.3,20.0,26.7,1]

def get_state(el):
 if 0 <= el < 10:
     return 1
 elif 10 <= el < 20:
     return 2
 elif 20 <= el < 30:
     return 3
 else:
     raise Exception(f"Unexpected value: {el}")

res = [get_state(el) for el in arr]
# [1, 1, 1, 2, 2, 1, 2, 1, 3, 3, 1]

Upvotes: 0

yatu
yatu

Reputation: 88285

If numpy is an option this is quite simple with np.digitize:

import numpy as np
a = np.array([1.2,4.6,3.7,11.2,13,5,18.9,0.3,20.0,26.7,1])

np.digitize(a, (0,10,20))
# array([1, 1, 1, 2, 2, 1, 2, 1, 3, 3, 1], dtype=int64)

Upvotes: 2

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