pandas python中的SQL查询

Question

我正在用python pandas编写一个SQL查询：

import pandas as pd
from pandas import DataFrame, read_csv
import numpy as np
from pandasql import sqldf
pysqldf=lambda q:sqldf(q,globals())
rolup = pysqldf(u"select MasterUserId,DeviceUsed,hcluster, count(MasterUserId) as Tot_Rec, sum(Visits),sum(PV),sum(TimeSpent) from clstrd_data group by MasterUserId,DeviceUsed,hcluster;")

错误：

sqlite3.ProgrammingError: You must not use 8-bit bytestrings unless you use a text_factory that can interpret 8-bit bytestrings (like text_factory = str). It is highly recommended that you instead just switch your application to Unicode strings.

如何切换到Unicode字符串？我正在使用python2.7。

Answer 1

根据python unicode howto的说法

In Python source code, Unicode literals are written as strings prefixed with the ‘u’ or ‘U’ character: u'abcdefghijk'

换句话说，你的脚本应该是这样的：

import pandas as pd
from pandas import DataFrame, read_csv
import numpy as np
from pandasql import sqldf
pysqldf=lambda q:sqldf(q,globals())
rolup = pysqldf(u"select MasterUserId,DeviceUsed,hcluster, count(MasterUserId) as Tot_Rec, sum(Visits),sum(PV),sum(TimeSpent) from clstrd_data group by MasterUserId,DeviceUsed,hcluster;")

希望这能有所帮助。