Redis in Python:hyperloglog (Pfadd, Pfcount, Pfmerge)

Redis Hyperloglog can accept multiple elements as input and give cardinality estimates of input elements.

Cardinality: The number of different elements in the collection. For example [foo ', ' Bar ', ' foobar ', ' bar ', ' test '}] the cardinality is 4.

Hyperloglog provides only three functions: Pfadd, Pfcount, Pfmerge

Pfadd:

Adds the specified element to the Hyperloglog.

Pfadd (Key, *values)

return value

Integer that returns 0 if at least one element is added to return 1.

Pfcount:

Returns the radix value of the specified hyperloglog.

Pfmerge:

Merges multiple hyperloglog into one hyperloglog.

Instance:

>>>ImportRedis>>> r =Redis. Redis ()>>> R.pfadd ('Hyperlog1', *['Foo','Bar','Foo','Foobar','Test'])1>>> R.pfcount ('Hyperlog1')4>>> R.pfadd ('hyperlog2', *['Foo','Bar','Mans','Xie','Xiemanrui'])1>>> R.pfcount ('hyperlog2')5>>> R.pfmerge ('Hyperlog1','hyperlog2') True>>> R.pfcount ('Hyperlog1')7>>>

Redis in Python:hyperloglog (Pfadd, Pfcount, Pfmerge)