将重复变量替换为＆＃34; NA＆＃34;使用awk

Question

假设我有下一个文件：

1 Blue
2 Red
3 Yellow
4 Yellow
5 Yellow
6 Purple
7 Purple
8 Green

我想得到以下文件，用＆＃34; NA＆＃34;

替换重复的变量

1 Blue
2 Red
3 Yellow
4 NA
5 NA
6 Purple
7 NA
8 Green

Answer 1

试试这个 -

$ awk 'a[$2]++{$2="NA"} 1' f
1 Blue
2 Red
3 Yellow
4 NA
5 NA
6 Purple
7 NA
8 Green

Answer 2

$ awk '{print $1, ($2==p ? "NA" : $2); p=$2}' file
1 Blue
2 Red
3 Yellow
4 NA
5 NA
6 Purple
7 NA
8 Green

Answer 3

def del_user_from_lists(user):
    user.user_lists.through.objects.filter(user_id=user.pk).delete()