在python中，通过对象中的字符串删除行

Question

我有以下数据，并试图删除dateTime列中有"!ENDMSG!"的所有行

                   dateTime  tradePrice  tradeVolume  aggVolume     bid1     ask1  quote_counter
33501  2017-09-19 15:59:53     12545.5          1.0    54344.0  12545.0  12545.5      1567101.0
33502  2017-09-19 15:59:59     12545.0          1.0    54345.0  12545.0  12545.5      1567136.0
33503  2017-09-19 16:00:00     12545.0          1.0    54346.0  12544.5  12545.0      1567146.0
33504  2017-09-19 16:03:44     12544.0         17.0    54363.0  12544.0  12544.0      1567519.0
33505             !ENDMSG!         NaN          NaN        NaN      NaN      NaN            NaN

问题是dateTime列的类型是object，因此所有以下选项失败：

df[df.dateTime.str.contains('!ENDMSDG!') == False]
df[~df.dateTime.str.contains("!")]
df = df[~df['dateTime'].str.contains('!ENDMSDG!')]
print(df[df['dateTime'].str.match('!ENDMSDG!')])#another try to catch it

谢谢你的建议

Answer 1

似乎需要将!ENDMSDG!更改为!ENDMSG!（而不是第二个D字母）：

df = df[~df['dateTime'].str.contains('!ENDMSG!')]

df = df[~df['dateTime'].str.contains('!')]
#alternative with disable regex
#df = df[~df['dateTime'].str.contains('!', regex=False)]

如果需要检查字符串的开头：

df = df[~df['dateTime'].str.startswith('!')]

print (df)
                  dateTime  tradePrice  tradeVolume  aggVolume     bid1  \
33501  2017-09-19 15:59:53     12545.5          1.0    54344.0  12545.0   
33502  2017-09-19 15:59:59     12545.0          1.0    54345.0  12545.0   
33503  2017-09-19 16:00:00     12545.0          1.0    54346.0  12544.5   
33504  2017-09-19 16:03:44     12544.0         17.0    54363.0  12544.0   

          ask1  quote_counter  
33501  12545.5      1567101.0  
33502  12545.5      1567136.0  
33503  12545.0      1567146.0  
33504  12544.0      1567519.0