pandas achieve hive of lag and lead functions

lag and lead

The function has the following format:

• The first parameter is the column name,
• The second parameter is the n-th line up (optional, defaults to 1),
• The third parameter is the default value (NULL behavior when the n-th time up, the default value, if not specified, compared with NULL)

lag

LAG (field name, N, the default value) over (Partition by grouping field Order  by sort field mode)

lead

Lead (field name, N, the default value) over (Partition by grouping field Order  by sort field mode)

 

Case:

select 
  cookieid, 
  createtime, 
  url, 
  row_number() over (partition by cookieid order by createtime) as rn, 
  LAG(createtime,1,'1970-01-01 00:00:00') over (partition by cookieid order by createtime) as last_1_time, 
  LAG(createtime,2) over (partition by cookieid order by createtime) as last_2_time 
from cookie.cookie4

 

 

 

select 
  cookieid, 
  createtime, 
  url, 
  row_number() over (partition by cookieid order by createtime) as rn, 
  LEAD(createtime,1,'1970-01-01 00:00:00') over (partition by cookieid order by createtime) as next_1_time, 
  LEAD(createtime,2) over (partition by cookieid order by createtime) as next_2_time 
from cookie.cookie4;

pandas window function to achieve

pandas shift function is used to implement lag / lead function