Returns the previous string value of a key after setting it to a new value.
GETSET key value
Atomically sets key to value and returns
the old value stored at key. Returns an error when
key exists but does not hold a string value. Any previous
time to live associated with the key is discarded on successful
SET operation.
GETSET can be used together with INCR for
counting with atomic reset. For example: a process may call
INCR against the key mycounter every time some
event occurs, but from time to time we need to get the value of the
counter and reset it to zero atomically. This can be done using
GETSET mycounter "0":
127.0.0.1:6379> INCR mycounter
(integer) 1
127.0.0.1:6379> GETSET mycounter "0"
"1"
127.0.0.1:6379> GET mycounter
"0"SET with the GET argument.
One of the following:
Bulk string reply: the old value stored at the key.
Nil reply: if the key does not exist.
One of the following:
Bulk string reply: the old value stored at the key.
Null reply: if the key does not exist.
O(1)
@fast @string @write
127.0.0.1:6379> SET mykey "Hello"
OK
127.0.0.1:6379> GETSET mykey "World"
"Hello"
127.0.0.1:6379> GET mykey
"World"APPEND, DECR, DECRBY, DELIFEQ, GET, GETDEL, GETEX, GETRANGE, INCR, INCRBY, INCRBYFLOAT, LCS, MGET, MSET, MSETNX, PSETEX, SET, SETEX, SETNX, SETRANGE, STRLEN, SUBSTR.