Use Pandas to split a csv

split_csv.py

import pandas as pd

count = 0

# Load csv as Pandas dataframe, set number of rows in each file to 9000
df = pd.read_csv('bigfile.csv', iterator=True, chunksize=9000) 

# Iterate over each chunk
for chunk in df:
    # Set output file name, appending count variable
    outname = 'out'
    outname += str(count)
    outname += '.csv'
    
    # Create files, increase count
    chunk.to_csv(outname, index=False)
    count += 1
    
    # There should probably be some error-handling here...