用: 位圖法 bit-map

Log0721:  ‘011001...............0’

......

log0726 :   ‘011001...............0’

Log0727 :  ‘0110000.............1’

1: 記錄用戶登陸:

每天按日期生成一個位圖, 用戶登陸后,把user_id位上的bit值置為1

2: 把1周的位圖  and 計算,

位上為1的,即是連續(xù)登陸的用戶

Redis 127.0.0.1:6379> setbit mon 100000000 0

(integer) 0

redis 127.0.0.1:6379> setbit mon 3 1

(integer) 0

redis 127.0.0.1:6379> setbit mon 5 1

(integer) 0

redis 127.0.0.1:6379> setbit mon 7 1

(integer) 0

redis 127.0.0.1:6379> setbit thur 100000000 0

(integer) 0

redis 127.0.0.1:6379> setbit thur 3 1

(integer) 0

redis 127.0.0.1:6379> setbit thur 5 1

(integer) 0

redis 127.0.0.1:6379> setbit thur 8 1

(integer) 0

redis 127.0.0.1:6379> setbit wen 100000000 0

(integer) 0

redis 127.0.0.1:6379> setbit wen 3 1

(integer) 0

redis 127.0.0.1:6379> setbit wen 4 1

(integer) 0

redis 127.0.0.1:6379> setbit wen 6 1

(integer) 0

redis 127.0.0.1:6379> bitop and  res mon feb wen

(integer) 12500001

如上例,優(yōu)點(diǎn):

1: 節(jié)約空間, 1億人每天的登陸情況,用1億bit,約1200WByte,約10M 的字符就能表示

2: 計算方便