Python aggregate functions

Description of the function/method name equivalent operator

All collection types

Len (s) set cardinality: The number of elements in the set S

Set ([obj]) variable set factory function; Obj must be an iteration supported by obj

Creates a collection of elements, or creates an empty collection

Frozenset ([obj]) immutable set factory function; The execution mode is the same as the set () method,

But it returns the immutable collection

Obj in S member test: is obj an element of s?

Obj not in S non-member test: is obj an element in s?

s = = t equivalence Test: Does the test S and t have the same elements?

s! = T is not equivalent to test: = = opposite

S < T (in strict sense) subset testing; s! = T and S in all

Elements are members of T

S.issubset (t) s <= T subset Test (allows for a subset of non-strict meanings): all elements in S

They're all members of T.

s > t (in strict sense) superset Test: s! = T and all elements of T

They're all members of S.

S.issuperset (t) s >= T-superset Test (allows for non-strict superset): all elements in t

They're all members of S.

S.union (t) s | T merge operation: elements in S or T

S.intersec-tion (t) S & T intersection operation: elements in S and T

S.difference (t) s-t differential operation: An element in S, not an element in T

S.symmetric_difference (t) s ^ t symmetric differential operation: elements in S or T, but not s and T are common

The Elements

S.copy () Copy operation: Returns a (shallow copy) copy of S

For mutable collections only

S.update (t) s |= T (Union) Modify operation: Add a member of T to the S

S.intersection_update (t) s &= T intersection modification operation: s includes only members of S and T

S.difference_update (t) s-= t Difference modification operation: s includes members that belong only to s but are not part of T

S.symmetric_

Difference_

Update (t) s ^= T symmetric differential modification operation: s contains only s or T-only

Members

S.add (obj) plus operation: adding obj to S

S.remove (obj) delete operation: Remove obj from S, if not present in S

obj, will throw Keyerror

S.discard (obj) Discard operation: A friendly version of remove ()-such as

There is an obj in the fruit s,

Remove it from S

S.pop () Pop operation: Remove and return any element in S

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Python aggregate functions