使用Python在Pandas dataframe中创建周几列
使用Python在Pandas dataframe中创建周几列
提问于 2015-05-14 02:24:12
使用Python在Pandas dataframe中创建周几列
我想将csv文件读入pandas数据帧，将一列日期从字符串格式解析为date对象，然后生成一个表示星期几的新列。
这就是我正在尝试的：
我想要做的是：
import pandas as pd
import csv
df = pd.read_csv('data.csv', parse_dates=['date']))
df['day-of-week'] = df['date'].weekday()
AttributeError: 'Series' object has no attribute 'weekday'谢谢你的帮助。詹姆斯
回答 7
Stack Overflow用户
回答已采纳
发布于 2015-05-14 02:36:36
熊猫0.23+
使用pandas.Series.dt.day_name()，因为pandas.Timestamp.weekday_name已被弃用：
import pandas as pd
df = pd.DataFrame({'my_dates':['2015-01-01','2015-01-02','2015-01-03'],'myvals':[1,2,3]})
df['my_dates'] = pd.to_datetime(df['my_dates'])
df['day_of_week'] = df['my_dates'].dt.day_name()输出：
my_dates myvals day_of_week
0 2015-01-01 1 Thursday
1 2015-01-02 2 Friday
2 2015-01-03 3 Saturday熊猫0.18.1+
正如用户jezrael在下面指出的，在0.18.1 Pandas Docs版本中添加了dt.weekday_name
import pandas as pd
df = pd.DataFrame({'my_dates':['2015-01-01','2015-01-02','2015-01-03'],'myvals':[1,2,3]})
df['my_dates'] = pd.to_datetime(df['my_dates'])
df['day_of_week'] = df['my_dates'].dt.weekday_name输出：
my_dates myvals day_of_week
0 2015-01-01 1 Thursday
1 2015-01-02 2 Friday
2 2015-01-03 3 Saturday原始答案：
使用以下命令：
http://pandas.pydata.org/pandas-docs/stable/generated/pandas.Series.dt.dayofweek.html
请看以下内容：
Get weekday/day-of-week for Datetime column of DataFrame
如果你想要一个字符串而不是一个整数，可以这样做：
import pandas as pd
df = pd.DataFrame({'my_dates':['2015-01-01','2015-01-02','2015-01-03'],'myvals':[1,2,3]})
df['my_dates'] = pd.to_datetime(df['my_dates'])
df['day_of_week'] = df['my_dates'].dt.dayofweek
days = {0:'Mon',1:'Tues',2:'Weds',3:'Thurs',4:'Fri',5:'Sat',6:'Sun'}
df['day_of_week'] = df['day_of_week'].apply(lambda x: days[x])输出：
my_dates myvals day_of_week
0 2015-01-01 1 Thurs
1 2015-01-02 2 Fri
2 2015-01-01 3 ThursStack Overflow用户
发布于 2016-05-09 03:10:04
在版本0.18.1中添加了dt.weekday_name
print df
my_dates myvals
0 2015-01-01 1
1 2015-01-02 2
2 2015-01-03 3
print df.dtypes
my_dates datetime64[ns]
myvals int64
dtype: object
df['day_of_week'] = df['my_dates'].dt.weekday_name()
print df
my_dates myvals day_of_week
0 2015-01-01 1 Thursday
1 2015-01-02 2 Friday
2 2015-01-03 3 Saturday另一种使用assign的解决方案
print df.assign(day_of_week = df['my_dates'].dt.weekday_name())
my_dates myvals day_of_week
0 2015-01-01 1 Thursday
1 2015-01-02 2 Friday
2 2015-01-03 3 SaturdayStack Overflow用户
发布于 2018-08-11 08:21:09
使用dt.weekday_name是deprecated since pandas 0.23.0，请改用dt.day_name()
df = pd.DataFrame({'my_dates':['2015-01-01','2015-01-02','2015-01-03'],'myvals':[1,2,3]})
df['my_dates'] = pd.to_datetime(df['my_dates'])
df['my_dates'].dt.day_name()
0 Thursday
1 Friday
2 Saturday
Name: my_dates, dtype: object页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/30222533
复制相关文章
相似问题