学习 redis 的基础命令

basically, redis is a data structure server

string list set sorted set hash

## key related

“`
keys list all keys share the pattern
exists key
del key
expire key expiration
expireat key timestamp
ttl key
rename key
type key
“`

## string related

“`
set key value set mystr “hello world”
setex key timeout value set key with expiration
setnx key value set only not exist
get key -> value get mystr
getset key new -> old get old and set new
setrange key offset value
getrange key start end returns the value, inclusive
mget key… returns a list of values
“`

“`
incr key mynum
decr key mynum
incrby key value mynum
decrby key value mynum
getset
“`

# hash

“`
hmset key f v … store kv pair in hash
hgetall key
hdel key f
hexists key f
hkeys key
hlen key
hvals key
“`

# lists

list is implemented as a double-linked list

“`
lpush key value1 value2 value3 lpushx only pushes if not exist
rpush
lpop key
rpop
rpoplpush src dst
blpop key… timeout block until one value is avaliable
lindex key index
llen key
lrange key start end inclusive
linsert key
lrem key count value
lset key index value
ltrim key start end
“`

# tricks

to get all elements with lrange: use `lrange KYE 0 -1`

# Persistense

RDB
AOF

# Transaction

“`
MULTI用来组装一个事务;
EXEC用来执行一个事务;
DISCARD用来取消一个事务;
WATCH用来监视一些key,一旦这些key在事务执行之前被改变,则取消事务的执行。
“`

# zset
rank is which place the value ranked by score in the zset.

## add and remove cookies

“`
zadd KEY SCORE MEMBER # add a value to a zset
zincrby KEY SCORE MEMBER # increment the member’s score NOTE redis-py implements wrongly
zrem KEY MEMBER… # remove a value from zset
zremrangebyrank KEY START STOP # removes all values in the set within the give index
zremrangebyscore KEY MIN MAX # removes all values in the set within the given scores
“`

## get zset stats

this is zismember command, just use zscore KEY MEMBER is None to check
“`
zcard KEY # get the number of elements in a zset
zcount KEY MIN MAX # count the members in a sorted set with scores within the given scores
zrank KEY MEMBER # get the index of member in zset
zrevrank KEY MEMBER # the reverse index of member
zscore KEY MEMBER # get the score of member in zset
“`

## read member(s)

“`
zrange KEY START END # a range of members by index
zrevrange KEY START END # a range of memvers by index, sorted from high to low
zrangebyscore KEY MIN MAX # a range of members within given scores
zrevrangebyscore KEY MAX MIN # a range of members within given scores, from max to min
“`

## set manipulation

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