CODEWITHSUNDEEP
pythonpandas
Nafisa Anjum Samia
Nafisa Anjum Samia

Reputation: 113

Random sampling from different class

I am totally new in this area. I tried to find the solutions but couldn't get exactly like this. I am doing the code in python Jupyter using pandas library. I know the code for sampling. Which is df = data.sample(frac =.1) But can't understand how to write the code for this.

Dataset:

enter image description here

I have this dataset. I want to choose 2 rows randomly from each class(Rings). Following is the expected output:

enter image description here

Upvotes: 1

Views: 1513

Answers (1)

Dani Mesejo
Dani Mesejo

Reputation: 61910

You could do the following:

Setup

import numpy as np
import pandas as pd

np.random.seed(42)

df = pd.DataFrame({"Shell(g)": np.random.random(14), "Rings": [3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6]})

Code

# shuffle
result = df.sample(frac=1.0)

# get the first two by group
result = result.groupby("Rings").head(2)

# sort by Rings
result = result.sort_values("Rings")

print(result)

Output

    Shell(g)  Rings
1   0.950714      3
0   0.374540      3
3   0.598658      4
2   0.731994      4
7   0.866176      5
6   0.058084      5
12  0.832443      6
10  0.020584      6

Upvotes: 2

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