pandas 将数据框列转换为浮动
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Converting a dataframe column to float
提问by Stacey
I have a dataframes called historic_pricewith two columns called 'price'and 'item'that I am trying to multiple together storing the result in a different data-frame called dayData, but I get the exception:
我有一个数据帧，historic_price其中有两列被调用'price'，'item'并且我试图将结果多个存储在一个名为 的不同数据帧中dayData，但我得到了异常：
TypeError: can't multiply sequence by non-int of type 'float'
The 'price'column looks like:
该'price'列看起来像：
price
0 5.86500
1 2.03000
2 13.55000
3 639.75450
4 343.94325
5 1009.43500
6 585.60600
7 2208.72400
8 807.54800
9 236.51530
10 14.34000
The 'item'column looks like:
该'item'列看起来像：
item
0 0.0
1 0.0
2 0.0
3 0.0
4 0.0
5 0.0
6 0.0
7 0.0
8 0.0
9 0.0
10 0.0
(I know all of the values are zero but even so when I multiple price by item I shoud still get a result (0))
（我知道所有的值都是零，但即便如此，当我按项目多个价格时，我仍然应该得到结果 (0)）
the data types for the two columns are both <class 'pandas.core.series.Series'>
两列的数据类型都是 <class 'pandas.core.series.Series'>
I am trying to add the product of item and price to the dayDatadataframe as follows:
我正在尝试将商品和价格的产品添加到dayData数据框中，如下所示：
dayData["cash"] = historicPrice["price"] * historicPrice["item"]
but I get the exception above.
但我得到了上面的例外。
I have tried converting the columns to float:
我曾尝试将列转换为浮动：
dayData["cash"] = float(historicPrice["price"]) * float(historicPrice["item"])
but with no luck (I get the exception: TypeError: cannot convert the series to <class 'float'>)
但没有运气（我得到异常：TypeError: cannot convert the series to <class 'float'>）
Can anyone let me know what i need to do to fix please?
任何人都可以让我知道我需要做什么来修复吗？
Many thanks
非常感谢
回答by Kamil Sindi
It's highly likely you have strings in one of the columns. Try using to_numeric with errors set to 'coerce':
您很可能在其中一列中有字符串。尝试使用 to_numeric 并将错误设置为“强制”：
df['price'] = pd.to_numeric(df['price'], errors='coerce').fillna(0)
df['item'] = pd.to_numeric(df['item'], errors='coerce').fillna(0)
df['cash'] = df['price'] * df['item']
