## decr, decrBy ##### Description Decrement the number stored at key by one. If the second argument is filled, it will be used as the integer value of the decrement. 对指定的KEY的值自减1。如何填写了第二个参数，将把第二个参数自减给KEY的值。##### Parameters *key* *value*: value that will be substracted to key (only for decrBy) ##### Return value *INT* the new value ##### Examples ``` <pre class="calibre9">$redis->decr('key1'); /* key1 didn't exists, set to 0 before the increment */ /* and now has the value -1 */ $redis->decr('key1'); /* -2 */ $redis->decr('key1'); /* -3 */ $redis->decrBy('key1', 10); /* -13 */ ```