KeyError：python 中的 1 个代码 - 无法解决问题

Question

这段代码曾经有效，现在不再有效。对于我的生活无法弄清楚什么是错的。我猜它与 for 循环有关，但仅此而已。

import pandas as pd

LastFY = 2017
n = 15

DeclRate = 0.1
Res = 442.364
LFY_Vol = 27.8

Col_Names = ['Year', 'Reserves', 'Prod']
df = pd.DataFrame(columns=Col_Names)
df_add = pd.DataFrame(columns=Col_Names)

df['Year'] = [LastFY]
df['Prod'] = [LFY_Vol]
df['Reserves'] = [Res]

for i in range(1, n+1):

    FY = df['Year'][i-1] + 1
    if df['Prod'][i-1] * (1 - DeclRate) > df['Reserves'][i-1]:
    Prod_A = df['Reserves'][i-1]
    else:
        Prod_A = df['Prod'][i-1] * (1 - DeclRate) if i < n else df['Reserves'][i-1]
    Reserves_A = df['Reserves'][i-1] - Prod_A

    df_add['Year'] = [FY]
    df_add['Reserves'] = [Reserves_A]
    df_add['Prod'] = [Prod_A]

df = df.append(df_add, ignore_index=True)
df.round(0).style

谢谢。

这是我得到的错误代码...

runfile('C:/Users.../TEST.py', wdir='C:/Users...')
Traceback (most recent call last):

  File "<ipython-input-175-365e0e41c561>", line 1, in <module>
    runfile('C:/Users.../TEST.py', wdir='C:/Users...')

  File "C:\ProgramData\Anaconda3\lib\site-packages\spyder\utils\site\sitecustomize.py", line 705, in runfile
    execfile(filename, namespace)

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

  File "C:/Users.../TEST.py", line 22, in <module>
    FY = df['Year'][i-1] + 1

  File "C:\ProgramData\Anaconda3\lib\site-packages\pandas\core\series.py", line 623, in __getitem__
    result = self.index.get_value(self, key)

  File "C:\ProgramData\Anaconda3\lib\site-packages\pandas\core\indexes\base.py", line 2560, in get_value
    tz=getattr(series.dtype, 'tz', None))

  File "pandas/_libs/index.pyx", line 83, in pandas._libs.index.IndexEngine.get_value

  File "pandas/_libs/index.pyx", line 91, in pandas._libs.index.IndexEngine.get_value

  File "pandas/_libs/index.pyx", line 139, in pandas._libs.index.IndexEngine.get_loc

  File "pandas/_libs/hashtable_class_helper.pxi", line 811, in pandas._libs.hashtable.Int64HashTable.get_item

  File "pandas/_libs/hashtable_class_helper.pxi", line 817, in pandas._libs.hashtable.Int64HashTable.get_item

KeyError: -1

Answer 1

您已将n 定义如下：

n = 15

然后您定义一个包含一行的数据框：

print(df)

   Year  Reserves  Prod
0  2017   442.364  27.8

然后你遍历range(1, 16):

for i in range(1, n+1):
    FY = df['Year'][i-1] + 1

但是，由于您的数据框只有一行索引为 0，df['Year'][1] 将返回 KeyError。这正是您应该期待的。

您还没有解释您要达到的目标。您可能希望在a new question 中这样做。上面的解释描述了为什么你得到了你的错误。一般来说，print 是一个有用的函数，可以确定每个阶段发生的情况。