Question

我下面列出了一个pd df。

  data={'Equipment_Class':['PC1', 'PC1', 'PC1', 'PC2', 'PC2', 'PC2','PC2'],
       'EL_base':['0','1','2','0','1','2','3'],
       'Installed Price': ['235.67', '236.50', '245.81', '506.66', 
                          '506.66','507.34','516.78'],
       'First Year Operating Cost': 
                          ['1.62','0.85','0.16','2.27','1.27','1.29','0.34'],
        'LCC Savings':['0.00','0.00','-3.27','0.00','7.92','7.48','5.20']}

  df=pd.DataFrame(data=data,columns=['Equipment_Class','EL_base','Installed Price',\
            'First Year Operating Cost','LCC Savings'])

我想在“ LCC储蓄”列之后添加另一列“简单PBP”。

新列的计算方法为：

     if "LCC savings" is 0, 0, 
      else ("Installed Price"- EL_base(0) Installed Price)/(EL_base(0)"First Year 
      Operating Cost"-"First Year Operating Cost"

例如：

        PC1, EL_base =2
        Simple PBP =(245.81-235.67)/(1.62-0.16)

此计算方法适用于每个设备组。我该怎么办？

Answer 1

那又怎么样：

#Cast to float
df[['Installed Price','First Year Operating Cost', 'LCC Savings']] = df[['Installed Price','First Year Operating Cost','LCC Savings']].astype(float)

# Get first prices out:
df[['install_0', 'fyoc0']] = df.groupby('Equipment_Class')[['Installed Price','First Year Operating Cost']].transform('first')

# Run calc
result = (df['Installed Price']-df['install_0'])/(df['First Year Operating Cost']-df['fyoc0'] )

# Mask rows to 0:
df['Simple PBP'] = result.mask(df["LCC Savings"]==0, 0)

编辑：错过了每个组的要求！更改答案。

Answer 2

您需要将数据框中的数字转换为...数字：

df['EL_base'] = df['EL_base'].astype('int')
df[['Installed Price', 'First Year Operating Cost', 'LCC Savings']] = df[['Installed Price', 'First Year Operating Cost', 'LCC Savings']].astype(float)

计算：

def calcualte_pbp(group):
    base = group[group['EL_base'] == 0].iloc[0]
    installed_price = group['Installed Price'] - base['Installed Price']
    fyoc = base['First Year Operating Cost'] - group['First Year Operating Cost']

    return group.assign(**{'Simple PBP': np.where(group['LCC Savings'] == 0, 0, installed_price / fyoc)})

df.groupby('Equipment_Class').apply(calcualte_pbp).reset_index(drop=True)

结果：

  Equipment_Class  EL_base  Installed Price  First Year Operating Cost  LCC Savings  Simple PBP
0             PC1        0           235.67                       1.62         0.00    0.000000
1             PC1        1           236.50                       0.85         0.00    0.000000
2             PC1        2           245.81                       0.16        -3.27    6.945205
3             PC2        0           506.66                       2.27         0.00    0.000000
4             PC2        1           506.66                       1.27         7.92    0.000000
5             PC2        2           507.34                       1.29         7.48    0.693878
6             PC2        3           516.78                       0.34         5.20    5.243523

新列的条件计算

2 个答案: