Python dictionary data type

  • A dictionary is a collection that is unordered, changeable, and indexed in nature.
  • The dictionaries are written with curly brackets { }.
  • Python dictionaries have keys and values.
Example

Create dictionary

d = { "name": "Ravi",
"brand": "NIELITBHU",
"year": 2000}
print(d)

Output

{ ‘name’: ‘Ravi’, ‘brand’: ‘NIELITBHU’, ‘year’: 2000 }

How to Access dictionary Items

  • To access list items by using the keyname, inside square brackets.
Example

Create dictionary

d = { "name": "Ravi",
"brand": "NIELITBHU",
"year": 2000}
c=d["name"]
print(c)

Output

Ravi

get method

  • You can also access the dictionary item using the get( ) method/function.
Example

Create dictionary

d = { "name": "Ravi",
"brand": "NIELITBHU",
"year": 2000}
c=d.get("name")
print(c)

Output

Ravi

Check if control statement in dictionary

  • Using in keywords to determine if a specified item is present in a  dictionary.
Example

Use of control statement in dictionary

d = { "name": "Ravi",
"brand": "NIELITBHU",
"year": 2000}


if 'brand' in d:
print("yes found")
else:
print("Not found")

Output

yes found

How to Change Item Value in dictionary

  • In a dictionary to change the value of a specific item by referring to its key name
Example

Use of control statement in dictionary

d = { "name": "Ravi",
"brand": "NIELITBHU",
"year": 2000}
print("before changing")
print(d)
d["year"]=2002
print("After changing")
print(d)

Output

before changing
{‘name’: ‘Ravi’, ‘brand’: ‘NIELITBHU’, ‘year’: 2000}
After changing
{‘name’: ‘Ravi’, ‘brand’: ‘NIELITBHU’, ‘year’: 2002}

To access dictionary of a member by using for loop.

using a for loop

Example

Use of for loop

d = { "name": "Ravi",
"brand": "NIELITBHU",
"year": 2000}
for x in d:
 print(x)

Output

name
brand
year
Example

Print all values

d = { "name": "Ravi",
"brand": "NIELITBHU",
"year": 2000}
for x in d:
 print(d[x])

Output

Ravi
NIELITBHU
2000
Example

values( ) : This function to return values of a dictionary.

d = { "name": "Ravi",
"brand": "NIELITBHU",
"year": 2000}
for x in d.values():
 print(x)

Output

Ravi
NIELITBHU
2000
Example

items() : This function return both keys and values.

d = { "name": "Ravi",
"brand": "NIELITBHU",
"year": 2000}
for x,y in d.items():
 print(x,y)

Output

name Ravi
brand NIELITBHU
year 2000
English Hindi