dictionary python

 # dictionary is used to store data values in key:value pairs

# aftrer 3.7 version-> ordered , mutable, do not allow duplicate keys

# key only be immutable dat type.

# student={

#     "name":"ved",

#     "subject":["python","java","c"],

#     "chapter":(1,2,3,4,5),

#     "roll_no":98,

#     "gender":"male",

#     "percentage":91.87,

#      1:520

# }

# print(student)

# print(type(student))

# access value through key-> if key is not present and we want to access then error

# print(student["name"])

# print(student[1])

# change value ->

# student["name"]="sam"

# print(student["name"])

# add another key value->

# student["surname"]="varshney"

# print(student)

# empty dictionary->

# null_dict={}

# print(type(null_dict))

# null_dict["name"]="ved"

# print(null_dict)

# nested dictionary

# student={

#     "name":"ved",

#     "age":22,

#     "roll":98,

#     "subjects":{

#         "phy":98,

#         "math":100,

#         "hindi":89,

#         "english":94

#     }

# }

# print(student["subjects"]["hindi"])

# methods of dictionary->

# 1- keys()->used to access all keys

# print(student.keys())

# 2- len()->

# print(len(student))

# 3- values()->used to access all values

# print(student.values())

# 4- items()-> returns all (key,value) pairs as tuples

# print(list(student.items()))          

# 5- get()-> retuen value of given key

# if enter wrong key in get() method , no error , get None.

# print(student.get("name"))

# 6- update(pair/new_dict)-> inserts the new_dict ot pair in dictioanry

# student.update({"city":"ghaziabad"})

# print(student)

# new_dict={

#     "capital":"up"

# }

# student.update(new_dict)

# print(student)

#  pop()-> remove item from dictionary

# student.pop("name")

# print(student)

# popitem()-> removes last added item from dictionary

# student.popitem()

# print(student)

# clear()-> removes all data

# student.clear()

# print(student)

dict={

    "a":100,

    "b":200,

    "c":300

}

sum=0

for x in dict:

    sum+=dict.get(x)

print(sum)