我正在可视化选举民意测验的数据集,并要求使用2012年10月的数据,但这给了我一个错误。
import pandas as pd
from pandas import Series,DataFrame
import numpy as np
poll_df=pd.read_csv('http://elections.huffingtonpost.com/pollster/2012-general-election-romney-vs-obama.csv')
row_in=0
xlimit=[]
for date in poll_df['Start Date']:
if date[0:7] == '2012-10':
xlimit.append(row_in)
row_in += 1
else:
row_in+=1
print(min(xlimit))
print(max(xlimit))
为什么给我这个错误,这是什么意思?
答案 0 :(得分:1)
使用:
url ='http://elections.huffingtonpost.com/pollster/2012-general-election-romney-vs-obama.csv'
具有日期时间的解决方案-将列转换为read_csv
中的date
s,然后按strftime
比较字符串并按boolean indexing
进行过滤:>
poll_df = pd.read_csv(url, parse_dates=['Start Date'])
df = poll_df[poll_df['Start Date'].dt.strftime('%Y-%m') == '2012-10']
print(df['Start Date'].dtype)
datetime64[ns]
带字符串的解决方案-通过indexing with str提取前7个值:
poll_df = pd.read_csv(url)
df = poll_df[poll_df['Start Date'].str[:7] == '2012-10']
print(df['Start Date'].dtype)
object
print(df.head())
Pollster Start Date End Date Entry Date/Time (ET) \
18 YouGov 2012-10-31 2012-11-03 2012-11-04T16:24:50Z
19 Pew 2012-10-31 2012-11-03 2012-11-04T15:46:59Z
21 Rasmussen 2012-10-31 2012-11-02 2012-11-03T10:54:09Z
22 Purple Strategies 2012-10-31 2012-11-01 2012-11-02T12:31:41Z
23 JZ Analytics/Newsmax 2012-10-30 2012-11-01 2012-11-02T22:57:27Z
Number of Observations Population Mode Obama Romney \
18 36472.0 Likely Voters Internet 49.0 47.0
19 2709.0 Likely Voters Live Phone 48.0 45.0
21 1500.0 Likely Voters Automated Phone 48.0 48.0
22 1000.0 Likely Voters IVR/Online 47.0 46.0
23 1030.0 Likely Voters Internet 48.0 46.0
Undecided Other Pollster URL \
18 3.0 NaN http://elections.huffingtonpost.com/pollster/p...
19 NaN 3.0 http://elections.huffingtonpost.com/pollster/p...
21 2.0 1.0 http://elections.huffingtonpost.com/pollster/p...
22 7.0 NaN http://elections.huffingtonpost.com/pollster/p...
23 6.0 NaN http://elections.huffingtonpost.com/pollster/p...
Source URL Partisan \
18 http://cdn.yougov.com/r/1/ygTabs_november_like... Nonpartisan
19 http://www.people-press.org/2012/11/04/obama-g... Nonpartisan
21 http://www.rasmussenreports.com/public_content... Nonpartisan
22 http://www.purplestrategies.com/wp-content/upl... Nonpartisan
23 http://www.jzanalytics.com/ Sponsor
Affiliation Question Text Question Iteration
18 None NaN 1
19 None NaN 1
21 None NaN 1
22 None NaN 1
23 Rep NaN 1