`module Lists`

Methods for managing Redis lists.

Definitions

`def blpop(*keys, timeout: 0)`

Remove and get the first element in a list, or block until one is available. O(1). See https://redis.io/commands/blpop for more details.

Signature

parameter　key　Key
parameter　timeout　Integer

Implementation

def blpop(*keys, timeout: 0)
	call("BLPOP", *keys, timeout)
end

`def brpop(*keys, timeout: 0)`

Remove and get the last element in a list, or block until one is available. O(1). See https://redis.io/commands/brpop for more details.

Signature

parameter　key　Key
parameter　timeout　Integer

Implementation

def brpop(*keys, timeout: 0)
	call("BRPOP", *keys, timeout)
end

`def brpoplpush(source, destination, timeout)`

Pop an element from a list, push it to another list and return it; or block until one is available. O(1). See https://redis.io/commands/brpoplpush for more details.

Signature

parameter　source　Key
parameter　destination　Key
parameter　timeout　Integer

Implementation

def brpoplpush(source, destination, timeout)
	call("BRPOPLPUSH", source, destination, timeout)
end

`def lindex(key, index)`

Get an element from a list by its index. O(N) where N is the number of elements to traverse to get to the element at index. This makes asking for the first or the last element of the list O(1). See https://redis.io/commands/lindex for more details.

Signature

parameter　key　Key
parameter　index　Integer

Implementation

def lindex(key, index)
	call("LINDEX", key, index)
end

`def linsert(key, position=:before, index, value)`

Insert an element before or after another element in a list. O(N) where N is the number of elements to traverse before seeing the value pivot. This means that inserting somewhere on the left end on the list (head) can be considered O(1) and inserting somewhere on the right end (tail) is O(N). See https://redis.io/commands/linsert for more details.

Signature

parameter　key　Key
parameter　where　Enum
parameter　pivot　String
parameter　element　String

Implementation

def linsert(key, position=:before, index, value)
	if position == :before
		offset = "BEFORE"
	else
		offset = "AFTER"
	end
	
	call("LINSERT", key, offset, index, value)
end

`def llen(key)`

Get the length of a list. O(1). See https://redis.io/commands/llen for more details.

Signature

parameter　key　Key

Implementation

def llen(key)
	call("LLEN", key)
end

`def lpop(key)`

Remove and get the first element in a list. O(1). See https://redis.io/commands/lpop for more details.

Signature

parameter　key　Key

Implementation

def lpop(key)
	call("LPOP", key)
end

`def lpush(key, value, *values)`

Prepend one or multiple elements to a list. O(1) for each element added, so O(N) to add N elements when the command is called with multiple arguments. See https://redis.io/commands/lpush for more details.

Signature

parameter　key　Key
parameter　element　String

Implementation

def lpush(key, value, *values)
	case value
	when Array
		values = value
	else
		values = [value] + values
	end
	
	call("LPUSH", key, *values)
end

`def lpushx(key, value)`

Prepend an element to a list, only if the list exists. O(1) for each element added, so O(N) to add N elements when the command is called with multiple arguments. See https://redis.io/commands/lpushx for more details.

Signature

parameter　key　Key
parameter　element　String

Implementation

def lpushx(key, value)
	call("LPUSHX", key, value)
end

`def lrange(key, start, stop)`

Get a range of elements from a list. O(S+N) where S is the distance of start offset from HEAD for small lists, from nearest end (HEAD or TAIL) for large lists; and N is the number of elements in the specified range. See https://redis.io/commands/lrange for more details.

Signature

parameter　key　Key
parameter　start　Integer
parameter　stop　Integer

Implementation

def lrange(key, start, stop)
	call("LRANGE", key, start, stop)
end

`def lrem(key, count, value)`

Remove elements from a list. O(N+M) where N is the length of the list and M is the number of elements removed. See https://redis.io/commands/lrem for more details.

Signature

parameter　key　Key
parameter　count　Integer
parameter　element　String

Implementation

def lrem(key, count, value)
	call("LREM", key, count, value)
end

`def lset(key, index, values)`

Set the value of an element in a list by its index. O(N) where N is the length of the list. Setting either the first or the last element of the list is O(1). See https://redis.io/commands/lset for more details.

Signature

parameter　key　Key
parameter　index　Integer
parameter　element　String

Implementation

def lset(key, index, values)
	call("LSET", key, index, values)
end

`def ltrim(key, start, stop)`

Trim a list to the specified range. O(N) where N is the number of elements to be removed by the operation. See https://redis.io/commands/ltrim for more details.

Signature

parameter　key　Key
parameter　start　Integer
parameter　stop　Integer

Implementation

def ltrim(key, start, stop)
	call("LTRIM", key, start, stop)
end

`def rpop(key)`

Remove and get the last element in a list. O(1). See https://redis.io/commands/rpop for more details.

Signature

parameter　key　Key

Implementation

def rpop(key)
	call("RPOP", key)
end

`def rpoplpush(source, destination=nil)`

Remove the last element in a list, prepend it to another list and return it. O(1). See https://redis.io/commands/rpoplpush for more details.

Signature

parameter　source　Key
parameter　destination　Key

Implementation

def rpoplpush(source, destination=nil)
	destination = source if destination.nil?
	
	call("RPOPLPUSH", source, destination)
end

`def rpush(key, value, *values)`

Append one or multiple elements to a list. O(1) for each element added, so O(N) to add N elements when the command is called with multiple arguments. See https://redis.io/commands/rpush for more details.

Signature

parameter　key　Key
parameter　element　String

Implementation

def rpush(key, value, *values)
	case value
	when Array
		values = value
	else
		values = [value] + values
	end
	
	call("RPUSH", key, *values)
end

`def rpushx(key, value)`

Append an element to a list, only if the list exists. O(1) for each element added, so O(N) to add N elements when the command is called with multiple arguments. See https://redis.io/commands/rpushx for more details.

Signature

parameter　key　Key
parameter　element　String

Implementation

def rpushx(key, value)
	call("RPUSHX", key, value)
end