Split CSVs

import pandas as pd
import numpy as np
import os

def splitCSVs(filename='',directory=os.getcwd(), num_of_files=3):

    if filename=='': raise ValueError("No filename entered")

    os.chdir(directory)
    df=pd.read_csv(filename)

    type_of_file=filename[len(filename)-filename[::-1].index('.')-1:]

    filename=filename[:filename.index(type_of_file)]


    print("Original length: %s"%(len(df)))

    incr=int(len(df)/num_of_files)
    parts=[]
    for i in range(num_of_files):
        parts.append((i+1)*incr)
    parts=parts[:-1]


    dfs=np.split(df,parts,axis=0)

    num=0
    for df_part in dfs:
        print('  length of part %s: %s'%(num,len(df_part)))
        df_part.to_csv(filename+'_part%s'%(num)+type_of_file, index=False)
        num+=1


filename='Digital Upload - Shinjuku Minamiguchi_20190312_part2_part1.csv'
directory='/home/cptawe/Desktop/datawise/Temp_Files/'
num_of_files=4

splitCSVs(filename,directory,4)