(Python) How to get the first/second/third modal Array in an Array?

Question

Please can someone tell me how i could get the most frequent/modal array out of an nested array?

So for example for:

a = np.array([[A, 8, 3, 0],[B, 8, 4, 0],[A, 8, 3, 0]])

The result should be [A, 8, 3, 0] with count 2.

I did my research on that problem, but only found solutions which compare one value of one dimension and not the whole arrays.

And is it possible to get the 2nd and 3rd most frequent array too?

Thank you in advance,

Greetings :)

Your example is not a correct / complete (numpy) array literal. As for the actual problem & solution, this question has already been asked and answered for example in [find the most frequent number in a numpy array](https://stackoverflow.com/questions/6252280/find-the-most-frequent-number-in-a-numpy-vector). Use a `collections.Counter` and convert your nested array to a nested tuple beforehand. — elemakil, Oct 04 '18 at 21:00

Abhishek Patel · Answer 1 · 2018-10-04T21:21:29.447

0

If you don't care about the order of the lists, then you can use set comparisons to find the most common element just as you would do if you had a list of integers.

L = [['A', 8, 3, 0],['B', 8, 4, 0],['A', 8, 3, 0]]
counter = 0
set = L[0]
for i in L:
    amount_times = L.count(i)
    if amount_times > counter:
        counter = amount_times
        set = i

print (set)
print (counter)`

edited Oct 04 '18 at 21:21

answered Oct 04 '18 at 21:02

Abhishek Patel

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This is a solution using the built in lists for python. A more specific answer for numpy arrays would be using the answer @mad_ provided – Abhishek Patel Oct 04 '18 at 21:05
Ok i will try this out tomorrow but that should work thank you :) – QWERASDFYXCV Oct 04 '18 at 21:18

score 0 · Answer 2 · answered Oct 04 '18 at 21:03

Using pandas

import pandas as pd
a = np.array([['A', 8, 3, 0],['B', 8, 4, 0],['A', 8, 3, 0]])
df=pd.DataFrame(a)
df=df.reset_index().groupby([0,1,2,3]).count().sort_values('index',ascending=False).reset_index()

np.array(df.iloc[0,0:4])

If you print you can find all the frequencies. HTH

(Python) How to get the first/second/third modal Array in an Array?

2 Answers2