'numpy.float64'对象没有属性'translate'在Python中插入值到Mysql

Question

import dataset 
db = dataset.connect(....) 
table = db[...] 

当我尝试向Mysql表中插入一些值时，发生此错误。

样本值，我插入到表：

print("Buy", ticker, price, date, OType, OSize) 
Buy AAPL 93.4357142857 2016-05-12 Market 200 
data = dict(Order_Side='Buy',Ticker=ticker, Price=price, 
          Order_Date= date, Order_Type = OType, Volume = OSize) 
table.insert(data) 

错误消息：

Traceback (most recent call last): 

    File "<ipython-input-3-b7ab0c98f72f>", line 1, in <module> 
    runfile('C:/Users/SwigelUser/Documents/GitHub/Trading/Strategies/strat_MA_ExecTest.py', wdir='C:/Users/SwigelUser/Documents/GitHub/Trading/Strategies') 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\spyder\utils\site\sitecustomize.py", line 880, in runfile 
    execfile(filename, namespace) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\spyder\utils\site\sitecustomize.py", line 102, in execfile 
    exec(compile(f.read(), filename, 'exec'), namespace) 

    File "C:/Users/SwigelUser/Documents/GitHub/Trading/Strategies/strat_MA_ExecTest.py", line 69, in <module> 
    MA_Stra(start_length=7,end_length=10,start_date=date(2016,5,12),end_date=date(2016,6,18)) 

    File "C:/Users/SwigelUser/Documents/GitHub/Trading/Strategies/strat_MA_ExecTest.py", line 66, in MA_Stra 
    table.insert(data1) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\dataset\persistence\table.py", line 87, in insert 
    res = self.database.executable.execute(self.table.insert(row)) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 945, in execute 
    return meth(self, multiparams, params) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\sqlalchemy\sql\elements.py", line 263, in _execute_on_connection 
    return connection._execute_clauseelement(self, multiparams, params) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 1053, in _execute_clauseelement 
    compiled_sql, distilled_params 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 1189, in _execute_context 
    context) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 1405, in _handle_dbapi_exception 
    util.reraise(*exc_info) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\sqlalchemy\util\compat.py", line 187, in reraise 
    raise value 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 1182, in _execute_context 
    context) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\sqlalchemy\engine\default.py", line 470, in do_execute 
    cursor.execute(statement, parameters) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\pymysql\cursors.py", line 164, in execute 
    query = self.mogrify(query, args) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\pymysql\cursors.py", line 143, in mogrify 
    query = query % self._escape_args(args, conn) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\pymysql\cursors.py", line 123, in _escape_args 
    return dict((key, conn.literal(val)) for (key, val) in args.items()) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\pymysql\cursors.py", line 123, in <genexpr> 
    return dict((key, conn.literal(val)) for (key, val) in args.items()) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\pymysql\connections.py", line 821, in literal 
    return self.escape(obj, self.encoders) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\pymysql\connections.py", line 814, in escape 
    return escape_item(obj, self.charset, mapping=mapping) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\pymysql\converters.py", line 27, in escape_item 
    val = encoder(val, mapping) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\pymysql\converters.py", line 110, in escape_unicode 
    return u"'%s'" % _escape_unicode(value) 

    File "C:\Users\SwigelUser\Anaconda3\lib\site-packages\pymysql\converters.py", line 73, in _escape_unicode 
    return value.translate(_escape_table) 

AttributeError: 'numpy.float64' object has no attribute 'translate' 

什么造成这个错误？我怎么能解决这个问题。 这似乎是我在这里输入了太多的代码，因此我必须输入很多无意义的代码才能提交。

我的价格和日期变量来自于一个数据帧：

for i in range(len(All_Tickers)-1-len(Current_Date),len(All_Tickers)-1): 
    price = All_Tickers[str(length) + 'day_MA'][i] 
    date = All_Tickers['Date'][i+1] 

根据下面的答案，这个问题应该是价格的类型是np.float64，我怎么能转换这个变量为float类型？

Answer 1

你的库试图将提供的参数格式化为MySQL将理解的格式。为此，它会检查每个参数的类型，以确定如何格式化输入。

但是，由于您的lib不知道numpy.float64，它会回退到默认编码器，这恰好是字符串（unicode）之一。 Here is the relevent piece of code。

def escape_item(val, charset, mapping=None): 
    if mapping is None: 
     mapping = encoders 
    encoder = mapping.get(type(val)) 

    # Fallback to default when no encoder found 
    if not encoder: 
     try: 
      encoder = mapping[text_type] 
     except KeyError: 
      raise TypeError("no default type converter defined") 

    if encoder in (escape_dict, escape_sequence): 
     val = encoder(val, charset, mapping) 
    else: 
     val = encoder(val, mapping) 
    return val 

此编码器，假设输入的确是一个字符串，试图调用此字符串的translate()方法。但是，由于这个方法没有为float64定义，所以你会得到这个错误。

您应该尝试将您的float64转换为常规浮动。

或者，您可以创建自己的编码器，并将其添加到用作Python类型到编码器的默认映射的encoders字典中。如果你打算用float64使用这个lib，这可能是值得的。