Redis: operation command for collecting set type data

  Collection types (set)

Redis Of Set yes string An unordered collection of types .

The general idea of data operation of collection type is through key Determine set ,key It's a collection id , The element has no subscript , Only the number of directly operated business data and data .

 

 

 

1.sadd

grammar ：sadd key member [member…]

function ： Put one or more member Elements are added to the collection key among , Existing in a collection member Elements will be ignored , Will not join .

Return value ： The number of new elements added to the collection ( Don't include elements that are ignored ).

  for example ：

 

 

2.smembers

grammar ：smembers key

function ： Get collection key All member elements in , There is no the key Treat as an empty set .

Return value ： Returns all elements of the specified set , There is no the key, Return empty set .

for example ：

 

 

3.sismember

grammar ：sismember key member

function ： Judge member Is the element a collection key The elements of

Return value ：member Is a collection member that returns 1, Other return 0 .

for example ：

 

4.scard

grammar ：scard key

function ： Get the number of elements in the collection

Return value ： Numbers ,key Number of elements of . Other situations return to 0 .

  for example ：

5.srem

grammar ：srem key member [member…]

function ： Remove one or more elements from the collection , Elements that do not exist are ignored .

Return value ： Numbers , Number of elements successfully removed , Don't include elements that are ignored .

 

for example ：

 

 

 

6.srandmember

grammar ：srandmember key[count]

function ： Only available key, Randomly returns an element in the set , The element is not deleted , Still in the collection ;

           Provides count when ,count Positive numbers , Return contains count A collection of several elements , Set elements do not repeat .count It's a negative number , Return to one count A collection of the lengths of absolute values , Elements in the collection may be repeated multiple times .

Return value ： A collection of one or more elements

 

  for example ：count Randomly generated

count： Number generated randomly count>0 No repetition count<0 There is repetition  

 

 

7.spop

grammar ：spop key[count]

function ： Randomly delete one or... From the set count Elements .

Return value ： Deleted elements ,key Nonexistent or empty collection returns nil.

for example ：

 

 

 

8.smove

grammar ：smove src dest member

function ： take member Elements from src The assembly moves to dest aggregate ,member non-existent ,smove Do not perform operation , return 0, If dest There is member, Only from src Delete in member.

Return value ： Successfully returns 1 , Other return 0 .

for example ：

 

 

9.sdiff

grammar ：sdiff key key [key…]

function ： Returns the difference of the specified set , Compare with the first set , That is, a set composed of elements in the first set but not in any other set .

Return value ： Returns a collection of elements in the first set that are not in the next set , If the elements in the first set are all in the subsequent set, an empty set is returned .

  for example ：

 

10.sinter

grammar ：sinter key key [key…]

function ： Returns the intersection of the specified set , That is, the set composed of elements in all specified sets .

Return value ： A collection of intersecting elements , If not, an empty collection is returned .

  for example ： At first 3 Sets have no working elements , And then when set02 Join in e Then there are common elements

 

11.sunion

grammar ：sunion key key [key…]

function ： Returns the union of the specified set , That is, a large set composed of all specified set elements , If the element repeats , Then keep one .

Return value ： Returns a large collection of all collection elements , If all key It doesn't exist , Return empty set .

  for example ：