# How to Pack and Unpack Data in Python — Tuples and Dictionaries

## Understand the magic asterisks (*)

May 8, 2020 · 5 min read
`>>> # Create a tuple>>> employee = ('John', 35, 'Male')>>> >>> # Create a dictionary>>> grades = {'John': 95, 'Jennifer': 92, 'Aaron': 98}`

## The Asterisk (*) Operator

`>>> # Multiplication with *>>> 3 * 26>>> # Exponentiation with **>>> 3 ** 327`

## Tuple Packing and Unpacking

`>>> # Create a tuple of prime numbers >>> primes = (2, 3, 5, 7, 11, 13)>>> >>> # Access elements using indexing>>> primes[0]2>>> # Access elements using an indexing range>>> primes[1:4](3, 5, 7)>>> # Access elements using reverse index>>> primes[-1]13`
`>>> # Create a tuple of prime numbers>>> primes = (2, 3, 5, 7, 11, 13)>>> >>> # Unpack the tuple, individually>>> a, b, c, d, e, f = primes>>> print(a, b, c, d, e, f, sep='||')2||3||5||7||11||13>>> >>> # Unpack the tuple, using the asterisk>>> p0, *p1, p2 = primes>>> print(p0, p1, p2, sep='||')2||[3, 5, 7, 11]||13>>> >>> # Check the type of p1>>> type(p1)<class 'list'>`
`>>> # Define a function with *args>>> def show_countries(*args):...     print(f"The args type: {type(args)}")...     for item in args:...         print(item)... >>> # Call the function>>> show_countries('America', 'Canada')The args type: <class 'tuple'>AmericaCanada`

## Dictionary Packing and Unpacking

`>>> # Define a function with **kwargs>>> def show_populations(**kwargs):...     print(f"The kwargs type: {type(kwargs)}")...     for key, value in kwargs.items():...         print(f"{key}: {value}")... >>> # Call the function>>> show_populations(America='328.2 million', Canada='37.59 million')The kwargs type: <class 'dict'>America: 328.2 millionCanada: 37.59 million`
`>>> # Declare a dictionary>>> grades0 = {'John': 95, 'Jennifer': 98}>>> >>> # Dictionary Unpacking>>> grades1 = {**grades0}>>> >>> # Aliasing>>> grades2 = grades0>>> >>> # Check the identities>>> grades1 is grades0False>>> grades2 is grades0True`
`>>> # Create two dictionaries >>> d1 = {'a': 1, 'b': 2}>>> d2 = {'c': 3, 'd': 4}>>> d2a = {'b': 20, 'c': 3, 'd':4}>>> >>> # Merge two dictionaries>>> d_merged0 = {**d1, **d2}>>> d_merged0{'a': 1, 'b': 2, 'c': 3, 'd': 4}>>> >>> # Merge two dictionaries having an overlapping key>>> d_merged1 = {**d1, **d2a}>>> d_merged1{'a': 1, 'b': 20, 'c': 3, 'd': 4}`

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Written by

## Yong Cui

Work at the nexus of biomedicine, data science & mobile dev. Love to write on these technological topics. Follow me @ycui01 on Twitter to get latest articles.

## The Startup

Get smarter at building your thing. Follow to join The Startup’s +8 million monthly readers & +787K followers.

Written by

## Yong Cui

Work at the nexus of biomedicine, data science & mobile dev. Love to write on these technological topics. Follow me @ycui01 on Twitter to get latest articles.

## The Startup

Get smarter at building your thing. Follow to join The Startup’s +8 million monthly readers & +787K followers.

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