collection

Sets

• Set are Unordered i.e. Its elements cannot be accessed by using Index.
• Set Can Contain Arbitrary Objects. i.e. any type of objects.
• Set are Mutable. i.e. contents of Set can be changed.
• Set are Dynamic. i.e. contents can be added or removed.
• Set cannot contain duplicate values. If given then they are ignored.
• Set Cannot Be Nested. i.e. a Set cannot contain another collection in it.
• A Python set is similar to mathematical Set.
• The major advantage of using a set, as opposed to a list, is that it has a highly optimized method for checking whether a specific element is contained in the set.
• This is based on a data structure known as a hash table. Its Items may appear in any order.
• There is no index attached to any element in a python set. So they do not support any indexing or slicing operation.

<set-name>={value1,value2,...,valueN}

Set Constructor

• The set() builtin creates a Python set from the given iterable.

<set_name>=set(iterable)

Months={"Jan","Feb","Mar"}
lst=["Mon","Tue","Wed","Thu","Fri","Sat","Sun"]
Days=set(lst)

  {'Feb', 'Mar', 'Jan'}
{'Mon', 'Tue', 'Wed', 'Fri', 'Sun', 'Sat', 'Thu'}

Accessing Values in a Set

• We cannot access individual values in a set.
• But we can get a list of individual elements by looping through the set.

for var in set-object:
    statement
    ---------

set Methods: