Write a Python code to select any one random row from a given DataFrame

Sometimes you need to select a random row from a Pandas DataFrame for sampling or testing purposes. Python provides several approaches to accomplish this task using iloc with random index generation or the sample() method.

Sample DataFrame

Let's start with a sample DataFrame to demonstrate the methods ?

import pandas as pd

data = {'Id': [1, 2, 3, 4, 5], 'Name': ['Adam', 'Michael', 'David', 'Jack', 'Peter']}
df = pd.DataFrame(data)
print("DataFrame is")
print(df)

DataFrame is
   Id     Name
0   1     Adam
1   2  Michael
2   3    David
3   4     Jack
4   5    Peter

Method 1: Using iloc with randrange()

Generate a random index using randrange() and select the row with iloc ?

import pandas as pd
import random as r

data = {'Id': [1, 2, 3, 4, 5], 'Name': ['Adam', 'Michael', 'David', 'Jack', 'Peter']}
df = pd.DataFrame(data)

rows = df.shape[0]
print("Total number of rows:", rows)

random_row = r.randrange(rows)
print("Random row is")
print(df.iloc[random_row, :])

Total number of rows: 5
Random row is
Id      3
Name    David
Name: 2, dtype: object

Method 2: Using sample() Method

The sample() method is the most efficient way to select random rows ?

import pandas as pd

data = {'Id': [1, 2, 3, 4, 5], 'Name': ['Adam', 'Michael', 'David', 'Jack', 'Peter']}
df = pd.DataFrame(data)

random_row = df.sample(n=1)
print("Random row using sample():")
print(random_row)

Random row using sample():
   Id   Name
1   2  Michael

Method 3: Using choice() with Index

Use numpy.random.choice() to select a random index ?

import pandas as pd
import numpy as np

data = {'Id': [1, 2, 3, 4, 5], 'Name': ['Adam', 'Michael', 'David', 'Jack', 'Peter']}
df = pd.DataFrame(data)

random_index = np.random.choice(df.index)
random_row = df.loc[random_index]
print("Random row using choice():")
print(random_row)

Random row using choice():
Id      4
Name    Jack
Name: 3, dtype: object

Comparison

Conclusion

The sample() method is the most Pythonic and efficient way to select random rows from a DataFrame. Use iloc with randrange() when you need to understand the underlying mechanics of random selection.