如何使用pandas数据帧计算列的x百分比

Question

I am trying to calculate x percentage of column value using pd.Series. I am getting error of NoneType. Not really sure what I'm doing wrong.

def PctMA(self, df, pct):
    pctName = 'PCT' + str(pct)
    pctDecimal = float(pct/100)
    pctCalulated = pd.Series((df['value'] - (df['value'] * pctDecimal)), name = pctName)
    df = df.join(pctCalulated)
    return df

I get the below error when I execute the code.

    pctCalulated = pd.Series((df['value'] - (df['value'] * pctDecimal)), name = pctName)
TypeError: 'NoneType' object has no attribute '__getitem__'

Below is the Expected results with Pct1 being generated as 1% column of value.

index   value   pct1
1   2476    2451.24
2   2475    2450.25
3   2486    2461.14
4   2536    2510.64
5   2453    2428.47
6   2486    2461.14
7   2648    2621.52
8   2563    2537.37
9   2756    2728.44

Answer 1

Maybe the error is not in the function but in the input, as I just used your code and it is working:

def PctMA(df, pct):
    pctName = 'PCT' + str(pct)
    pctDecimal = float(pct/100)
    pctCalulated = pd.Series((df['value'] - (df['value'] * pctDecimal)), name = pctName)
    df = df.join(pctCalulated)

    return df

df = pd.DataFrame({'value': [2476,2476,2486,2536]})
df_1 = PctMA(df, pct)
df_1

It is better to give more details.

Answer 2

I executed your code with minimal changes (just to map with 1% value). below is the code i executed, it is working absolutely fine. Issue with your input.