检查pandas里面的重复数据

我有以下代码：

import pandas as pd
import datetime
import pandas as pd
from pandas_datareader import data as web
import matplotlib.pyplot as plt
from alpha_vantage.foreignexchange import ForeignExchange
import os
from os import path
from alpha_vantage.timeseries import TimeSeries 
import matplotlib.pyplot as plt 
import sys



while True:
    if path.exists('stockdata.csv') == True:
        data1 = pd.read_csv('stockdata.csv')
        ts = TimeSeries(key='1ORS1XLM1YK1GK9Y', output_format='pandas')
        data, meta_data = ts.get_intraday(symbol = 'spy', interval='1min', outputsize='full')
        data = data.rename(columns={'1. open':'Open','2. high': 'High','3. low': 'Low', '4. close':'Close', '5. volume': 'Volume'})
        data1 = data1.append(data)
        data1.to_csv('stockdata.csv', sep= ' ')
        break
    else:
        data1 = pd.DataFrame(columns=['Open','High','Low', 'Close','Volume'])
        data1.to_csv('stockdata.csv', sep= ' ')

我想做的是检查文件stockdata.csv是否在当前目录中。如果找不到，则创建文件。 如果找到该文件，则下载数据data，并将该数据附加到data1.csv文件中并保存。

问题：

1.我如何摆脱Unnamed:0专栏？为什么在那里？ 2.我如何检查并删除其中的重复数据data并将其附加到data1？