为什么会有nameerror：这个列表变量中没有定义name[variable]？[副本]

Question

  File "C:/Users/Asus/Google Drive/Sun Gleam & Fine Works/System Improvement/Accounting/Voucher Reports/Voucher Reports", line 12, in <module>
    summary_name[i] = data_listofaccounts['Account Name']
NameError: name 'summary_name' is not defined

import pandas as pd
import matplotlib.pyplot as plt

entries_csv = "C:\\Users\\Asus\\Desktop\\Entries.csv"
listofaccounts_csv = "C:\\Users\\Asus\\Desktop\\List of Accounts.csv"

data_entries = pd.read_csv(entries_csv)
data_listofaccounts = pd.read_csv(listofaccounts_csv)

i = 0
for account_name in data_listofaccounts['Account Name']:
    summary_name[i] = data_listofaccounts['Account Name']
    for debit_account in data_entries['DEBIT ACCOUNT']:
        if account_name == debit_account:
            summary[i] += data_entries['DEBIT AMOUNT']
    i += 1

for p in range(i):
    print(summary[p])
    print(summary_name[p])

Answer 1

这个

summary_name[i]

假定已经存在名称为summary_name并允许使用[i]进行访问的内容。因为Python是一种动态语言，所以它可以是任何东西。在对象上使用[i]所需要的就是实现object.__getitem__读取和object.__setitem__写入。Python应该如何知道您希望summary_name作为执行此操作的众多类中的哪个类的实例？

因此，首先必须定义summary_name，例如作为一个空列表

summary_name = ["I", "am", "a", "list"]

summary_name = ("I", "am", "a", "tuple")

summary_name = "I am a string."

summary_name = [None] * 100