How to perform lrange + (delete the result of lrange from list) on Redis list

Question

I am aware that rpop removes the last element of the Redis list.How to pop items of list between certain range (eg: 0 to 100)?

I hope this is the combination of lrange + rpop.

Answer 1

To select and remove the first 100 elements (from the left):

LRANGE list 0 99
LTRIM list 100 -1

To select and remove the last 100 elements (from the right):

LRANGE list -1 -100
LTRIM list 0 -99

From an older version of the redis documentation for LTRIM:

Trim the list name, removing all values not within the slice between start and end. start and end can be negative numbers just like Python slicing notation

Answer 2

You need to combine lrange and ltrim to achieve this.

http://redis.io/commands/ltrim

Edit : As suggested in the comments the right answer is

lrange list 0 99
ltrim list 100 -1

Answer 3

remove the first top 100 element,should be:

lrange list 0 99 ltrim list 100 -1

remove the tail top 100 element,should be:

lrange list -100 -1 ltrim list 0 -101

Answer 4

As far as I know, there is no predefined command to pop a range of items from a list. You have to send a series of rpop commands to redis. It's usual with Redis to send many short commands, so it's not a problem to send 100 (or even 1000) rpop commands in a row. To improve performances you can send multiple command in one operation using "pipelining". The exact way of doing this depends on your driver.

Another way would be to write a Lua script and send it using eval