[Database] Redis (2) redis-py API Reference

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　　Redis 是一个高性能的key-value数据库。 它支持存储的value类型包括string、hash、list、set 和 zset等。redis还支持各种不同方式的排序。
　　All the commands available in Redis 2.0.0.  
API Reference
append(self, key, value)
　　Appends the string value to the value at key. If key  doesn't already exist, create it with a value of value.  Returns the new length of the value at key.
bgrewriteaof(self)
　　Tell the Redis server to rewrite the AOF file from data in memory.
bgsave(self)
　　Tell the Redis server to save its data to disk.  Unlike save(),  this method is asynchronous and returns immediately.
blpop(self, keys, timeout=0)
　　LPOP a value off of the first non-empty list  named in the keys list.
　　If none of the lists in keys has a value to LPOP, then block  for timeout seconds, or until a value gets pushed on to one  of the lists.
　　If timeout is 0, then block indefinitely.
brpop(self, keys, timeout=0)
　　RPOP a value off of the first non-empty list  named in the keys list.
　　If none of the lists in keys has a value to LPOP, then block  for timeout seconds, or until a value gets pushed on to one  of the lists.
　　If timeout is 0, then block indefinitely.
dbsize(self)
　　Returns the number of keys in the current database
decr(self, name, amount=1)
　　Decrements the value of key by amount.  If no key exists,  the value will be initialized as 0 - amount
delete(self, *names)
　　Delete one or more keys specified by names
encode(self, value)
　　Encode value using the instance's charset
execute_command(self, *args, **options)
　　Sends the command to the redis server and returns it's response
exists(self, name)
　　Returns a boolean indicating whether key name exists
expire(self, name, time)
　　Set an expire flag on key name for time seconds
expireat(self, name, when)
　　Set an expire flag on key name. when can be represented  as an integer indicating unix time or a Python datetime object.
flush(self, all_dbs=False)
flushall(self)
　　Delete all keys in all databases on the current host
flushdb(self)
　　Delete all keys in the current database
get(self, name)
　　Return the value at key name, or None of the key doesn't exist
get_connection(self, host, port, db, password, socket_timeout)
　　Returns a connection object
getset(self, name, value)
　　Set the value at key name to value if key doesn't exist  Return the value at key name atomically
hdel(self, name, key)
　　Delete key from hash name
hexists(self, name, key)
　　Returns a boolean indicating if key exists within hash name
hget(self, name, key)
　　Return the value of key within the hash name
hgetall(self, name)
　　Return a Python dict of the hash's name/value pairs
hincrby(self, name, key, amount=1)
　　Increment the value of key in hash name by amount
hkeys(self, name)
　　Return the list of keys within hash name
hlen(self, name)
　　Return the number of elements in hash name
hmget(self, name, keys)
　　Returns a list of values ordered identically to keys
hmset(self, name, mapping)
　　Sets each key in the mapping dict to its corresponding value  in the hash name
hset(self, name, key, value)
　　Set key to value within hash name  Returns 1 if HSET created a new field, otherwise 0
hsetnx(self, name, key, value)
　　Set key to value within hash name if key does not  exist.  Returns 1 if HSETNX created a field, otherwise 0.
hvals(self, name)
　　Return the list of values within hash name
incr(self, name, amount=1)
　　Increments the value of key by amount.  If no key exists,  the value will be initialized as amount
info(self)
　　Returns a dictionary containing information about the Redis server
keys(self, pattern='*')
　　Returns a list of keys matching pattern
lastsave(self)
　　Return a Python datetime object representing the last time the  Redis database was saved to disk
lindex(self, name, index)
　　Return the item from list name at position index
　　Negative indexes are supported and will return an item at the  end of the list
listen(self)
　　Listen for messages on channels this client has been subscribed to
llen(self, name)
　　Return the length of the list name
lock(self, name, timeout=None, sleep=0.10000000000000001)
　　Return a new Lock object using key name that mimics  the behavior of threading.Lock.
　　If specified, timeout indicates a maximum life for the lock.  By default, it will remain locked until release() is called.
　　sleep indicates the amount of time to sleep per loop iteration  when the lock is in blocking mode and another client is currently  holding the lock.
lpop(self, name)
　　Remove and return the first item of the list name
lpush(self, name, value)
　　Push value onto the head of the list name
lrange(self, name, start, end)
　　Return a slice of the list name between  position start and end
　　start and end can be negative numbers just like  Python slicing notation
lrem(self, name, value, num=0)
　　Remove the first num occurrences of value from list name
　　If num is 0, then all occurrences will be removed
lset(self, name, index, value)
　　Set position of list name to value
ltrim(self, name, start, end)
　　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
mget(self, keys, *args)
　　Returns a list of values ordered identically to keys

• Passing *args to this method has been deprecated *
  

move(self, name, db)
　　Moves the key name to a different Redis database db
mset(self, mapping)
　　Sets each key in the mapping dict to its corresponding value
msetnx(self, mapping)
　　Sets each key in the mapping dict to its corresponding value if  none of the keys are already set
parse_response(self, command_name, catch_errors=False, **options)
　　Parses a response from the Redis server
ping(self)
　　Ping the Redis server
pipeline(self, transaction=True)
　　Return a new pipeline object that can queue multiple commands for  later execution. transaction indicates whether all commands  should be executed atomically. Apart from multiple atomic operations,  pipelines are useful for batch loading of data as they reduce the  number of back and forth network operations between client and server.
pop(self, name, tail=False)
　　Pop and return the first or last element of list name
　　This method has been deprecated, use Redis.lpop or Redis.rpop instead.
psubscribe(self, patterns)
　　Subscribe to all channels matching any pattern in patterns
publish(self, channel, message)
　　Publish message on channel.  Returns the number of subscribers the message was delivered to.
punsubscribe(self, patterns=[])
　　Unsubscribe from any channel matching any pattern in patterns.  If empty, unsubscribe from all channels.
push(self, name, value, head=False)
　　Push value onto list name.
　　This method has been deprecated, use Redis.lpush or Redis.rpush instead.
randomkey(self)
　　Returns the name of a random key
rename(self, src, dst, **kwargs)
　　Rename key src to dst

• The following flags have been deprecated *If preserve is True, rename the key only if the destination name  doesn't already exist
  

renamenx(self, src, dst)
　　Rename key src to dst if dst doesn't already exist
rpop(self, name)
　　Remove and return the last item of the list name
rpoplpush(self, src, dst)
　　RPOP a value off of the src list and atomically LPUSH it  on to the dst list.  Returns the value.
rpush(self, name, value)
　　Push value onto the tail of the list name
sadd(self, name, value)
　　Add value to set name
save(self)
　　Tell the Redis server to save its data to disk,  blocking until the save is complete
scard(self, name)
　　Return the number of elements in set name
sdiff(self, keys, *args)
　　Return the difference of sets specified by keys
sdiffstore(self, dest, keys, *args)
　　Store the difference of sets specified by keys into a new  set named dest.  Returns the number of keys in the new set.
select(self, db, host=None, port=None, password=None, socket_timeout=None)
　　Switch to a different Redis connection.
　　If the host and port aren't provided and there's an existing  connection, use the existing connection's host and port instead.
　　Note this method actually replaces the underlying connection object  prior to issuing the SELECT command.  This makes sure we protect  the thread-safe connections
set(self, name, value, **kwargs)
　　Set the value at key name to value

• The following flags have been deprecated *If preserve is True, set the value only if key doesn't alreadyexistIf getset is True, set the value only if key doesn't already existand return the resulting value of key
  

setex(self, name, value, time)
　　Set the value of key name to value  that expires in time seconds
setnx(self, name, value)
　　Set the value of key name to value if key doesn't exist
sinter(self, keys, *args)
　　Return the intersection of sets specified by keys
sinterstore(self, dest, keys, *args)
　　Store the intersection of sets specified by keys into a new  set named dest.  Returns the number of keys in the new set.
sismember(self, name, value)
　　Return a boolean indicating if value is a member of set name
smembers(self, name)
　　Return all members of the set name
smove(self, src, dst, value)
　　Move value from set src to set dst atomically
sort(self, name, start=None, num=None, by=None, get=None, desc=False, alpha=False, store=None)
　　Sort and return the list, set or sorted set at name.
　　start and num allow for paging through the sorted data
　　by allows using an external key to weight and sort the items.  Use an "*" to indicate where in the key the item value is located
　　get allows for returning items from external keys rather than the  sorted data itself.  Use an "*" to indicate where int he key  the item value is located
　　desc allows for reversing the sort
　　alpha allows for sorting lexicographically rather than numerically
　　store allows for storing the result of the sort into  the key store
spop(self, name)
　　Remove and return a random member of set name
srandmember(self, name)
　　Return a random member of set name
srem(self, name, value)
　　Remove value from set name
subscribe(self, channels)
　　Subscribe to channels, waiting for messages to be published
substr(self, name, start, end=-1)
　　Return a substring of the string at key name. start and end  are 0-based integers specifying the portion of the string to return.
sunion(self, keys, *args)
　　Return the union of sets specifiued by keys
sunionstore(self, dest, keys, *args)
　　Store the union of sets specified by keys into a new  set named dest.  Returns the number of keys in the new set.
ttl(self, name)
　　Returns the number of seconds until the key name will expire
type(self, name)
　　Returns the type of key name
unsubscribe(self, channels=[])
　　Unsubscribe from channels. If empty, unsubscribe  from all channels
zadd(self, name, value, score)
　　Add member value with score score to sorted set name
zcard(self, name)
　　Return the number of elements in the sorted set name
zincr(self, key, member, value=1)
　　This has been deprecated, use zincrby instead
zincrby(self, name, value, amount=1)
　　Increment the score of value in sorted set name by amount
zinter(self, dest, keys, aggregate=None)
zinterstore(self, dest, keys, aggregate=None)
　　Intersect multiple sorted sets specified by keys into  a new sorted set, dest. Scores in the destination will be  aggregated based on the aggregate, or SUM if none is provided.
zrange(self, name, start, end, desc=False, withscores=False)
　　Return a range of values from sorted set name between  start and end sorted in ascending order.
　　start and end can be negative, indicating the end of the range.
　　desc indicates to sort in descending order.
　　withscores indicates to return the scores along with the values.   The return type is a list of (value, score) pairs
zrangebyscore(self, name, min, max, start=None, num=None, withscores=False)
　　Return a range of values from the sorted set name with scores  between min and max.
　　If start and num are specified, then return a slice of the range.
　　withscores indicates to return the scores along with the values.  The return type is a list of (value, score) pairs
zrank(self, name, value)
　　Returns a 0-based value indicating the rank of value in sorted set  name
zrem(self, name, value)
　　Remove member value from sorted set name
zremrangebyrank(self, name, min, max)
　　Remove all elements in the sorted set name with ranks between  min and max. Values are 0-based, ordered from smallest score  to largest. Values can be negative indicating the highest scores.  Returns the number of elements removed
zremrangebyscore(self, name, min, max)
　　Remove all elements in the sorted set name with scores  between min and max. Returns the number of elements removed.
zrevrange(self, name, start, num, withscores=False)
　　Return a range of values from sorted set name between  start and num sorted in descending order.
　　start and num can be negative, indicating the end of the range.
　　withscores indicates to return the scores along with the values  as a dictionary of value => score
zrevrank(self, name, value)
　　Returns a 0-based value indicating the descending rank of  value in sorted set name
zscore(self, name, value)
　　Return the score of element value in sorted set name
zunion(self, dest, keys, aggregate=None)
zunionstore(self, dest, keys, aggregate=None)
　　Union multiple sorted sets specified by keys into  a new sorted set, dest. Scores in the destination will be  aggregated based on the aggregate, or SUM if none is provided.