If i have a data frame of 100 rows, then how can i save a csv file of 21 row to 45 row ?

Here is an example of how you can save a csv file from row 21 to 45 of a data frame in Python:               import pandas as pd

# Load your data frame

df = pd.read_csv('your_data_frame.csv')

# Select rows 21 to 45

df = df[20:45]

# Save the new data frame as a csv file

df.to_csv('subset_of_your_data_frame.csv', index=False)                                                               .

Note that the index starts from 0, so the 21st row is indexed as 20 and the 45th row is indexed as 44