python提取多页PDF表格数据

import pdfplumber as pr
import pandas as pd
pdf = pr.open('21.PDF')
ps = pdf.pages
i1 = 0
table1 = [[0 for i in range(20)] for j in range(200)]
for p in range(9):
    pg = ps[p]
    tables = pg.extract_tables()
    table = tables[0]
    print(table)
    df = pd.Dataframe(table[1:],columns = table[0])

    for i in range(len(table)):
        for j in range(len(table[i])):
            #table[i][j] = table[i][j].replace('n','')
            table1[i1][j] = table[i][j]
        i1 = i1+1
    df1 = pd.Dataframe(table1[1:],columns = table1[0])
    df1.to_excel('1.xlsx')