在遍历列表后接收列表中变量的 NaN

Question

我有一份组成 ETF 的股票清单。我已将代码格式化为列表并将此变量命名为 assets

print(assets)
['AUD', 'CRWD', 'SPLK', 'OKTA', 'AVGO', 'CSCO', 'NET', 'ZS', 'AKAM', 'FTNT', 'BAH', 'CYBR', 'CHKP', 'BA/', 'VMW', 'PFPT', 'PANW', 'VRSN', 'FFIV', 'JNPR', 'LDOS', '4704', 'FEYE', 'QLYS', 'SAIC', 'RPD', 'HO', 'MIME', 'SAIL', 'VRNS', 'ITRI', 'AVST', 'MANT', 'TENB', '053800', 'ZIXI', 'OSPN', 'RDWR', 'ULE', 'MOBL', 'ATEN', 'TUFN', 'RBBN', 'NCC', 'KRW', 'EUR', 'JPY', 'GBP', 'USD']

我使用下面的for循环遍历列表并从yahoo

中提取历史数据

for i in assets:
    try:
          df[i] = web.DataReader(i, data_source='yahoo', start=start, end=end)['Adj Close']
   except RemoteDataError:
    print(f'{i}')
    continue

我返回：

BA/
4704
H0
053800
KRW
JPY

提示在yahoo finance 上找不到这些资产。我理解这种情况并接受。

当我在 yahoo finance 上寻找理论上已经找到的股票（例如 df['FEYE']）时，我得到以下信息。

0 NaN 1 NaN 2 NaN 3 NaN 4 NaN 5 NaN 6 NaN 7 NaN 8 NaN 9 NaN 10 NaN 11 NaN 12 NaN 13 NaN 14 NaN 15 NaN 16 NaN 17 NaN 18 NaN 19 NaN 20 NaN 21 NaN 22 NaN 23 NaN 24 NaN 25 NaN 26 NaN 27 NaN 28 NaN 29 NaN 30 NaN 31 NaN 32 NaN 33 NaN 34 NaN 35 NaN 36 NaN 37 NaN 38 NaN 39 NaN 40 NaN 41 NaN 42 NaN 43 NaN 44 NaN 45 NaN 46 NaN 47 NaN 48 NaN 名称：FEYE，数据类型：float64

当我正常进行时只有一股

（例如 CSCO = web.DataReader(assets[5], data_source='yahoo', start=start, end=end)['Adj Close']）

一切正常

非常感谢任何帮助，

谢谢！

Answer 1

这是代码和输出的可重现测试示例。如果您有名为 df 的现有数据框，则新数据在索引和列名方面不兼容。需要创建新的数据框，但在循环之外。每次迭代都会创建带有代码数据的新列。

import pandas as pd
import pandas_datareader.data as web
from pandas_datareader._utils import RemoteDataError

assets=['AUD', 'CRWD', 'SPLK', 'OKTA', 'AVGO', 'CSCO', 'NET', 'ZS', 'AKAM', 'FTNT', 'BAH', 'CYBR', 'CHKP', 'BA/', 'VMW', 'PFPT', 'PANW', 'VRSN', 'FFIV', 'JNPR', 'LDOS', '4704', 'FEYE', 'QLYS', 'SAIC', 'RPD', 'HO', 'MIME', 'SAIL', 'VRNS', 'ITRI', 'AVST', 'MANT', 'TENB', '053800', 'ZIXI', 'OSPN', 'RDWR', 'ULE', 'MOBL', 'ATEN', 'TUFN', 'RBBN', 'NCC', 'KRW', 'EUR', 'JPY', 'GBP', 'USD']

df = pd.DataFrame()
for i in assets:
    try:
        print(f'Try: {i}')
        df[i] = web.DataReader(i, data_source='yahoo')['Adj Close']
    except RemoteDataError as r:
        print(f'Try: {i}: {r}')
        continue

结果：

Try: AUD
Try: CRWD
Try: SPLK
Try: OKTA
Try: AVGO
Try: CSCO
Try: NET
Try: ZS
Try: AKAM
Try: FTNT
Try: BAH
Try: CYBR
Try: CHKP
Try: BA/
Try: BA/: Unable to read URL: https://finance.yahoo.com/quote/BA//history?period1=1435975200&period2=1593741599&interval=1d&frequency=1d&filter=history
Response Text:
b'<html>\n<meta charset=\'utf-8\'>\n<script>\nvar u=\'https://www.yahoo.com/?err=404&err_url=https%3a%2f%2ffinance.yahoo.com%2fquote%2fBA%2f%2fhistory%3fperiod1%3d1435975200%26period2%3d1593741599%26interval%3d1d%26frequency%3d1d%26filter%3dhistory\';\nif(window!=window.top){\n  document.write(\'<p>Content is currently unavailable.</p><img src="//geo.yahoo.com/p?s=1197757039&t=\'+new Date().getTime()+\'&_R=\'+encodeURIComponent(document.referrer)+\'&err=404&err_url=\'+u+\'" width="0px" height="0px"/>\');\n}else{\n  window.location.replace(u);\n}\n</script>\n<noscript><META http-equiv="refresh" content="0;URL=\'https://www.yahoo.com/?err=404&err_url=https%3a%2f%2ffinance.yahoo.com%2fquote%2fBA%2f%2fhistory%3fperiod1%3d1435975200%26period2%3d1593741599%26interval%3d1d%26frequency%3d1d%26filter%3dhistory\'"></noscript>\n</html>\n'
Try: VMW
Try: PFPT
Try: PANW
Try: VRSN
Try: FFIV
Try: JNPR
Try: LDOS
Try: 4704
Try: 4704: No data fetched for symbol 4704 using YahooDailyReader
Try: FEYE
Try: QLYS
Try: SAIC
Try: RPD
Try: HO
Try: HO: No data fetched for symbol HO using YahooDailyReader
Try: MIME
Try: SAIL
Try: VRNS
Try: ITRI
Try: AVST
Try: MANT
Try: TENB
Try: 053800
Try: 053800: No data fetched for symbol 053800 using YahooDailyReader
Try: ZIXI
Try: OSPN
Try: RDWR
Try: ULE
Try: MOBL
Try: ATEN
Try: TUFN
Try: RBBN
Try: NCC
Try: KRW
Try: KRW: No data fetched for symbol KRW using YahooDailyReader
Try: EUR
Try: JPY
Try: JPY: No data fetched for symbol JPY using YahooDailyReader
Try: GBP

请注意有两种类型的错误：

当代码不存在时，例如“HO”
由于“BA/”中的“/”导致结果 URL 错误

结果集数据框的头部df.head():

                  AUD  CRWD       SPLK  OKTA  ...   NCC  EUR         GBP        USD
Date                                          ...                                  
2015-11-03  51.500000   NaN  57.139999   NaN  ...  3.45  NaN  154.220001  13.608685
2015-12-22  55.189999   NaN  54.369999   NaN  ...  3.48  NaN  148.279999  13.924644
2015-12-23  55.560001   NaN  56.509998   NaN  ...  3.48  NaN  148.699997  14.146811
2015-12-24  55.560001   NaN  56.779999   NaN  ...  3.48  NaN  149.119995  14.324224
2015-12-28  56.270000   NaN  57.660000   NaN  ...  3.48  NaN  148.800003  14.057305

[5 rows x 43 columns]

希望对您有所帮助。

在遍历列表后接收列表中变量的 NaN

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