Pandas – Slice large dataframe into chunks

You can use list comprehension to split your dataframe into smaller dataframes contained in a list.

n = 200000  #chunk row size
list_df = [df[i:i+n] for i in range(0,df.shape[0],n)]

Or use numpy array_split:

list_df = np.array_split(df, n)

You can access the chunks with:

list_df[0]
list_df[1]
etc...

Then you can assemble it back into a one dataframe using pd.concat.

By AcctName

list_df = []

for n,g in df.groupby('AcctName'):
    list_df.append(g)