python - 如何使用 df.iterrows() 匹配同一列中的前一行值？

Question

我正在尝试使用索引号将前一行值与特定值进行匹配。 但我不知道如何实现这一点。 您能帮我解决这个问题吗？

示例:

operator_type   Operator
    =            None
    =            AND
    =            None
    =            OR
    =            None
    =            None

我正在尝试的代码:

for index, row in df.iterrows():
       if row['Operator'] == None and row['operator_type'] == '=' and row['Operator'].(index-1).values != 'AND':
             print('alka')

错误:

File "imed_cons_new.py", line 68
    if row['and_or_not_oprtor'] == None and row['operator_type'] == '=' and row['and_or_not_oprtor'].(index-1).values != 'AND':
                                                                                                     ^
SyntaxError: invalid syntax

Answer 1

你应该尝试“shift()”

df['previous'] = df['Operator'].shift()

for index, row in df.iterrows():
   if row['Operator'] == None and row['operator_type'] == '=' and row['previous'] != 'AND':
     print(index,'alka')

输出:

0 alka
4 alka
5 alka