Class: Redis::List

Inherits:
BaseObject show all
Includes:
Enumerable, Helpers::CoreCommands, Helpers::Serialize
Defined in:
lib/redis/list.rb

Overview

Class representing a Redis list. Instances of Redis::List are designed to behave as much like Ruby arrays as possible.

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Helpers::Serialize

#from_redis, #to_redis

Methods included from Helpers::CoreCommands

#exists?, #expire, #expireat, #move, #rename, #renamenx, #sort, #ttl, #type

Methods inherited from BaseObject

#initialize

Constructor Details

This class inherits a constructor from Redis::BaseObject

Instance Attribute Details

#key ⇒ Object (readonly)

Returns the value of attribute key.



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# File 'lib/redis/list.rb', line 16

def key
  @key
end

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/redis/list.rb', line 16

def options
  @options
end

#redis ⇒ Object (readonly)

Returns the value of attribute redis.



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# File 'lib/redis/list.rb', line 16

def redis
  @redis
end

Instance Method Details

#<<(value) ⇒ Object

Works like push. Can chain together: list << ‘a’ << ‘b’



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# File 'lib/redis/list.rb', line 19

def <<(value)
  push(value)
  self  # for << 'a' << 'b'
end

#==(x) ⇒ Object 



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# File 'lib/redis/list.rb', line 119

def ==(x)
  values == x
end

#[](index, length = nil) ⇒ Object Also known as: slice

Same functionality as Ruby arrays. If a single number is given, return just the element at that index using Redis: LINDEX. Otherwise, return a range of values using Redis: LRANGE.



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# File 'lib/redis/list.rb', line 56

def [](index, length=nil)
  if index.is_a? Range
    last = index.exclude_end? ? (index.last - 1) : index.last
    range(index.first, last)
  elsif length
    case length <=> 0
    when 1  then range(index, index + length - 1)
    when 0  then []
    when -1 then nil  # Ruby does this (a bit weird)
    end
  else
    at(index)
  end
end

#at(index) ⇒ Object

Return the value at the given index. Can also use familiar list syntax. Redis: LINDEX



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# File 'lib/redis/list.rb', line 94

def at(index)
  from_redis redis.lindex(key, index)
end

#delete(name, count = 0) ⇒ Object

Delete the element(s) from the list that match name. If count is specified, only the first-N (if positive) or last-N (if negative) will be removed. Use .del to completely delete the entire key. Redis: LREM



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# File 'lib/redis/list.rb', line 76

def delete(name, count=0)
  redis.lrem(key, count, to_redis(name))  # weird api
end

#each(&block) ⇒ Object

Iterate through each member of the set. Redis::Objects mixes in Enumerable, so you can also use familiar methods like collect, detect, and so forth.



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# File 'lib/redis/list.rb', line 82

def each(&block)
  values.each(&block)
end

#empty? ⇒ Boolean

Returns true if there are no elements in the list. Redis: LLEN == 0

Returns:

  • (Boolean) 


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# File 'lib/redis/list.rb', line 115

def empty?
  length == 0
end

#first ⇒ Object

Return the first element in the list. Redis: LINDEX(0)



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# File 'lib/redis/list.rb', line 99

def first
  at(0)
end

#last ⇒ Object

Return the last element in the list. Redis: LINDEX(-1)



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# File 'lib/redis/list.rb', line 104

def last
  at(-1)
end

#length ⇒ Object Also known as: size

Return the length of the list. Aliased as size. Redis: LLEN



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# File 'lib/redis/list.rb', line 109

def length
  redis.llen(key)
end

#pop ⇒ Object

Remove a member from the end of the list. Redis: RPOP



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# File 'lib/redis/list.rb', line 31

def pop
  from_redis redis.rpop(key)
end

#push(value) ⇒ Object

Add a member to the end of the list. Redis: RPUSH



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# File 'lib/redis/list.rb', line 25

def push(value)
  redis.rpush(key, to_redis(value))
  redis.ltrim(key, -options[:maxlength], -1) if options[:maxlength]
end

#range(start_index, end_index) ⇒ Object

Return a range of values from start_index to end_index. Can also use the familiar list Ruby syntax. Redis: LRANGE



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# File 'lib/redis/list.rb', line 88

def range(start_index, end_index)
  from_redis redis.lrange(key, start_index, end_index)
end

#shift ⇒ Object

Remove a member from the start of the list. Redis: LPOP



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# File 'lib/redis/list.rb', line 42

def shift
  from_redis redis.lpop(key)
end

#to_s ⇒ Object 



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# File 'lib/redis/list.rb', line 123

def to_s
  values.join(', ')
end

#unshift(value) ⇒ Object

Add a member to the start of the list. Redis: LPUSH



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# File 'lib/redis/list.rb', line 36

def unshift(value)
  redis.lpush(key, to_redis(value))
  redis.ltrim(key, 0, options[:maxlength] - 1) if options[:maxlength]
end

#values ⇒ Object Also known as: get

Return all values in the list. Redis: LRANGE(0,-1)



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# File 'lib/redis/list.rb', line 47

def values
  v = from_redis range(0, -1)
  v.nil? ? [] : v
end