We can use List, Tuple and Set to represent a group of individual objects as a single

entity.

֍ If we want to represent a group of objects as key-value pairs then we should go for

Dictionary.

Eg:

 rollno ---- name

 phone number -- address

 ipaddress --- domain name

֍ Duplicate keys are not allowed but values can be duplicated.

֍ Hetrogeneous objects are allowed for both key and values.

֍ Insertion order is not preserved

֍ Dictionaries are mutable

֍ Dictionaries are dynamic

֍ indexing and slicing concepts are not applicable

Note: In C++ and Java Dictionaries are known as "Map" where as in Perl and Ruby it is

known as "Hash"