Question

我正在尝试使用Python将多个网页中的数据导入到数据表中。基本上，自2000年以来，我一直在尝试下载某些团队的出勤数据。

这是我到目前为止所拥有的：

import requests
import pandas as pd
import numpy as np

#What is the effect of a rival team's performance on a team's attendance

Teams = ['LAA', 'LAD', 'NYY', 'NYM', 'CHC', 'CHW', 'OAK', 'SFG']
Years = []
for year in range(2000,2020):
    Years.append(str(year))

bbattend = pd.DataFrame(columns=['GM_Num','Date','Team','Home','Opp','W/L','R','RA','Inn','W-L','Rank','GB','Time','D/N','Attendance','Streak','Game_Win','Wins','Losses','Net_Wins'])

for team in Teams:
    for year in Years:
        url = 'https://www.baseball-reference.com/teams/' + team + '/' + year +'-schedule-scores.shtml'
        html = requests.get(url).content
        df_list = pd.read_html(html)
        df = df_list[-1]

        #Formatting data table
        df.rename(columns={"Gm#": "GM_Num", "Unnamed: 4": "Home", "Tm": "Team", "D/N": "Night"}, inplace = True)
        df['Home'] = df['Home'].apply(lambda x: 0 if x == '@' else 1)
        df['Game_Win'] = df['W/L'].astype(str).str[0]
        df['Game_Win'] = df['Game_Win'].apply(lambda x: 0 if x == 'L' else 1)
        df['Night'] = df['Night'].apply(lambda x: 1 if x == 'N' else 0)
        df['Streak'] = df['Streak'].apply(lambda x: -1*len(x) if '-' in x else len(x))
        df.drop('Unnamed: 2', axis=1, inplace = True)
        df.drop('Orig. Scheduled', axis=1, inplace = True)
        df.drop('Win', axis=1, inplace = True)
        df.drop('Loss', axis=1, inplace = True)
        df.drop('Save', axis=1, inplace = True)
        #Drop rows that do not have data
        df = df[df['GM_Num'].str.isdigit()]
        WL = df["W-L"].str.split("-", n = 1, expand = True)
        df["Wins"] = WL[0].astype(dtype=np.int64)
        df["Losses"] = WL[1].astype(dtype=np.int64)
        df['Net_Wins'] = df['Wins'] - df['Losses']
        bbattend.append(df)

bbattend

当我通过使用特定链接而不是尝试使用串联来创建url来分别在循环中执行操作时，这似乎起作用。

但是，使用此代码，我得到了错误：

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-77-997e6aeea77e> in <module>
     16         url = 'https://www.baseball-reference.com/teams/' + team + '/' + year +'-schedule-scores.shtml'
     17         html = requests.get(url).content
---> 18         df_list = pd.read_html(html)
     19         df = df_list[-1]
     20         #Formatting data table

~/anaconda3/lib/python3.7/site-packages/pandas/io/html.py in read_html(io, match, flavor, header, index_col, skiprows, attrs, parse_dates, tupleize_cols, thousands, encoding, decimal, converters, na_values, keep_default_na, displayed_only)
   1092                   decimal=decimal, converters=converters, na_values=na_values,
   1093                   keep_default_na=keep_default_na,
-> 1094                   displayed_only=displayed_only)

~/anaconda3/lib/python3.7/site-packages/pandas/io/html.py in _parse(flavor, io, match, attrs, encoding, displayed_only, **kwargs)
    914             break
    915     else:
--> 916         raise_with_traceback(retained)
    917 
    918     ret = []

~/anaconda3/lib/python3.7/site-packages/pandas/compat/__init__.py in raise_with_traceback(exc, traceback)
    418         if traceback == Ellipsis:
    419             _, _, traceback = sys.exc_info()
--> 420         raise exc.with_traceback(traceback)
    421 else:
    422     # this version of raise is a syntax error in Python 3

ValueError: No tables found

我不太明白错误消息在说什么。我将不胜感激！

Answer 1

因为某些页面中没有任何表格，例如this page和this page

因此，df_list = pd.read_html(html)将提高ValueError: No tables found。

您应该在此处使用try-except。

尝试使用Loop从网站导入数据时出现错误

1 个答案: