pandas 断言错误：通过了 22 列，传递的数据有 21 列
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AssertionError: 22 columns passed, passed data had 21 columns
提问by Aditya Gade
This is my code:
这是我的代码：
from urllib import urlopen
from bs4 import BeautifulSoup
import pandas as pd
url = "http://www.basketball-reference.com/draft/NBA_2014.html"
html = urlopen(url)
soup = BeautifulSoup(html)
column_headers = [th.getText() for th in soup.findAll('tr',limit=2)[1].findAll('th')]
data_rows = soup.findAll('tr')[2:]
player_data = [[td.getText() for td in data_rows[i].findAll('td')] for i in range(len(data_rows))] #PLAYER DATA
type(soup)
type(data_rows)
df = pd.DataFrame(player_data,columns=column_headers)
The error seems to occur in the last line.
错误似乎发生在最后一行。
回答by marts
First of all, the error is pretty straight-forward: your column_headerslist has 22 columns, but player_dataentries only have 21. So you need to find which out column is missing and why. Just by visually comparing the entries from the dataframe and the headers list, it appears one of the two first columns is missing. player_data[0][0]returns
首先，错误非常简单：您的column_headers列表有 22 列，但player_data条目只有 21。因此您需要找出缺少哪一列以及原因。仅通过直观地比较数据框和标题列表中的条目，似乎缺少前两列之一。player_data[0][0]回报
1, CLE, Andrew Wiggins, University of Kansas,...but it should be
1, CLE, Andrew Wiggins, University of Kansas,...但应该是
1, 1, CLE, Andrew Wiggins, University of Kansas,...
1, 1, CLE, Andrew Wiggins, University of Kansas,...
The problem is the table itself. Navigate to the website, hover over the table and right-click: inspect.
问题是桌子本身。导航到该网站，将鼠标悬停在表格上并右键单击：inspect。
The first row of data (underneath the 'Rk') consists of 21 tdand 1 thelement. The "rk" entry is actually of type thand not td:
第一行数据（在“Rk”下方）由 21td和 1 个th元素组成。“rk”条目实际上是类型th而不是td：
That is why your
这就是为什么你的
player_data = [[td.getText() for td in data_rows[i].findAll('td')] for i in range(len(data_rows))]
skips the first column because it is only iterating over tdelements. Hence the different length.
I don't know how important the first column is; quick fix would be to drop the Rk column from your headers list.
跳过第一列，因为它只迭代td元素。因此长度不同。我不知道第一列有多重要；快速解决方法是从标题列表中删除 Rk 列。
Alternatively, search for both tdand thelements:
另外，搜索都td和th元素：
player_data = [[td.getText() for td in data_rows[i].findAll(['td','th'])] for i in range(len(data_rows))]
