Dictionaries

A dictionary maps keys to values and in some languages it is known as an associative array.

{k1:v1,k2:v2}

Where k1,k2 are keys and v1,v2 are values

Create a dictionary

>>> students={"bob":90,"tom":50,"ram":70} # Create a dictionary

>>> students["ram"] # access by key                          
70

>>> students["dora"]=30 # adds a new element in dictionary

if key is not available a new key, value pair is added else value is updated

>>> students["dora"]=40
>>> students
{'bob': 90, 'tom': 50, 'ram': 70, 'dora': 40}

Remove an element with key bob

>>> del students["bob"]

>>> students={"bob":90,"tom":50,"ram":70}
>>> del students

>>> students={"bob":90,"tom":50,"ram":70}
>>> for key in students:
...  print(key,students[key])
...
bob 90
tom 50
ram 70

Note: key is not a key word

items() method return all the elements in key,value pair

>>> for key,value in students.items():
...  print(key,value)
...
bob 90
tom 50
ram 70