名称错误：name 'df' is not defined（名称'df'未定义）错误，因为df DataFrame被重新分配给第10行中的空DataFrame：

df = pd.DataFrame({})

你可以把它去掉

import pandas as pd

df = pd.read_csv('JOB205DAYREP.csv', header=0)
df = df.drop([0],axis=0)
df = df.dropna(axis=0, how='all')
df = df.dropna(axis=1, how='all')

for index, row in df.iterrows():
    if pd.isnull(row['FLT']) or row ['FLT'] == 'NA':
        df.at[index, 'FLT'] = df.at[index-1, 'FLT']
    
    if pd.isnull(row['STD']) or row ['STD'] == 'NA':
        df.at[index,'STD'] = df.at[index-1, 'STD']

    else:
        row['STD'] = fltdate + row ['STD']
    if not index==0 :
        if pd.isnull(row['VIAOFF']) or row['VIAOFF'] == 'NA':
            df.at[index, 'VIAOFF'] = df.at[index-1, 'VIAOFF']
        if pd.isnull(row['DEP']) or row['DEP'] == 'NA':
            df.at[index, 'DEP'] = df.at[index-1, 'DEP']

# Check if a string is a real valid date
from dateutil.parser import parse
date_string = '21/01/2023'
try :
    if parse(date_string, fuzzy=True, dayfirst=True) is not None:
        print('The string is a valid date.')
    else:
        print('The string is not a valid date.')
except Exception as e:
    error ='error'

如果现在起作用了就报告，希望能有所帮助。

应为“read_csv”。打字错误。