Tuples

• A list is a mutable data type. Mutable data can be updated anytime.

• Tuple is a immutable data. It can not be modified.

>>> tuple1 = (1, 2, 3)
>>> print(tuple1)
(1, 2, 3)
>>> tuple2 = 1, 2, 3
>>> print(tuple2)
(1, 2, 3)

Read data from a tuple: same as we do in a list

>>> tuple1 = (1, 2, 3)
>>> for item in tuple1:
        print(item)
1
2
3
>>> print(tuple1[0:1])
(1,)

Tuples can’t be modified

>>> tuple1 = (1, 2, 3)
>>> tuple1.append(4)
AttributeError: 'tuple' object has no attribute 'append'
>>> tuple1[4] = 9
TypeError: 'tuple' object does not support item assignment
>>> del tuple1[1]
TypeError: 'tuple' object doesn't support item deletion

A tuple can contain any type of data

>>> age = 22
>>> tuple1 = (1, "arindam", age, (1, 2))

>>> tuple2 = (1,)
>>> tuple3 = 1,

Dictionaries

>>> usernames = {
        "lydia": "lydiahallie"
        "sarah": "sarah123"
        "soma": "soma23"
        "ari": "123ari"
    }

A dictionary consists of keys and values; together, they make key-value pairs.

>>> print(usernames["sarah"])
sarah123
>>> print(usernames["hamilton")
KeyError: 'hamilton'

To get/ access the value of a dictionary using the key.

Important methods for dictionaries to read the data

• dictionary.keys()

• dictionary.values()

• dictionary.items()

keys() method - returns the key list

>>> usernames = {
        "lydia": "lydiahallie"
        "sarah": "sarah123"
        "soma": "soma23"
        "ari": "123ari"
    }
>>> print(usernames.keys())
dict_keys(['lydia', 'sarah', 'soma', 'ari'])

>>> usernames = {
        "lydia": "lydiahallie"
        "sarah": "sarah123"
        "soma": "soma23"
        "ari": "123ari"
    }
>>> for key in usernames.keys():
        print(key + "-" + usernames[key])

lydia - lydiahallie
sarah - sarah123
soma - soma23
ari - 123ari

values() method - return the values list

>>> usernames = {
        "lydia": "lydiahallie"
        "sarah": "sarah123"
        "soma": "soma23"
        "ari": "123ari"
    }
>>> print(usernames.values())
dict_values(['lydiahallie', 'sarah123', 'soma23', '123ari'])

items() method - return the tuples

>>> usernames = {
        "lydia": "lydiahallie"
        "sarah": "sarah123"
        "soma": "soma23"
        "ari": "123ari"
    }
>>> print(usernames.items())
dict_items([('lydia', 'lydiahallie'), ('sarah', 'sarah123'), ('soma', 'soma23'), ('ari','123ari')])

Modify data in a dictionary

>>> usernames = {
        "lydia": "lydiahallie"
        "sarah": "sarah123"
        "soma": "soma23"
        "ari": "123ari"
    }
>>> usernames["soma"] = "123soma"
>>> print(usernames["soma"])
"123soma"

Update dictionary by adding new key-value pairs

>>> usernames = {
        "lydia": "lydiahallie"
        "sarah": "sarah123"
        "soma": "soma23"
        "ari": "123ari"
    }
>>> usernames.update({"chloe": "chloe123"})
>>> print(usernames)
    {
        "lydia": "lydiahallie"
        "sarah": "sarah123"
        "soma": "soma23"
        "ari": "123ari"
        "chloe": "chloe123"
    }

Deleting data from dictionary

>>> del usernames["soma"]
>>> print(usernames)
    {
        "lydia": "lydiahallie"
        "sarah": "sarah123"
        "ari": "123ari"
        "chloe": "chloe123"
    }

Delete all items from a dictionary

>>> usernames.clear()
>>> print(usernames)
{}

Removing the last item from a dictionary

>>> usernames.popitem()

Copy a dictionary

>>> usernames_copy = usernames.copy()

References

Kodekloud