Python pandas - 返回指数值列
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pandas - return column of exponential values
提问by Fabio Lamanna
Starting from a sample dataframe dflike:
从示例数据帧开始，df例如：
a,b
0,0.71
1,0.75
2,0.80
3,0.90
I would add a new column with exponential values of column b. So far I tried:
我将添加一个具有 column 指数值的新列b。到目前为止，我尝试过：
df['exp'] = math.exp(df['b'])
but this method returns:
但此方法返回：
"cannot convert the series to {0}".format(str(converter)"
TypeError: cannot convert the series to <type 'float'>
Is there a way to apply a mathfunction to a whole column?
有没有办法将math函数应用于整列？
采纳答案by EdChum
Well math.expdoesn't understand Seriesdatatype, use numpy np.expwhich does and is vectorised so operates on the entire column:
好吧math.exp不理解Series数据类型，使用 numpynp.exp它可以并且被向量化，因此对整个列进行操作：
In [24]:
df['exp'] = np.exp(df['b'])
df
Out[24]:
a b exp
0 0 0.71 2.033991
1 1 0.75 2.117000
2 2 0.80 2.225541
3 3 0.90 2.459603
回答by Talis
try using:
尝试使用：
df['exp'] = df.b.apply(np.exp)
