满足特定条件时将数据填充到数据框中

Question

id       date         idx   comments
 1       01-05-2018    0      null
 2       02-05-2018    0      null
 3       03-05-2018    Y      null
 4       04-05-2018    Y      null 

当 idx = 0时，评论列需要更新为'，对于ID（提及相应ID）和日期（提及相应的日期）”

Answer 1

将list comprehension与zip和f-strings结合使用：

df['comments'] = [f'flow reported as null for id {i} and date {d}' if idx == '0' else 'NULL' 
                  for i, d, idx in zip(df['id'], df['date'], df['idx'])]

   id        date idx                                           comments
0   1  01-05-2018   0  flow reported as null for id 1 and date 01-05-...
1   2  02-05-2018   0  flow reported as null for id 2 and date 02-05-...
2   3  03-05-2018   Y                                               NULL
3   4  04-05-2018   Y                                               NULL

或使用apply：

df['comments'] = (
    df.apply(lambda x: f'flow reported as null for id {x["id"]} and date {x["date"]}' 
             if x['idx'] == '0' else 'NULL', axis=1)
)