Creating dictionary from two sequences in Python - Quick Revision & Summary

Recall & Review

beginner

What Python function can you use to pair elements from two sequences to create a dictionary?

You can use the zip() function to pair elements from two sequences, then pass it to dict() to create a dictionary.

beginner

Given two lists keys = ['a', 'b', 'c'] and values = [1, 2, 3], how do you create a dictionary from them?

Use dict(zip(keys, values)) to create {'a': 1, 'b': 2, 'c': 3}.

intermediate

What happens if the two sequences have different lengths when creating a dictionary with dict(zip(keys, values))?

The zip() function stops at the shortest sequence, so the dictionary will only include pairs up to that length.

beginner

Can you create a dictionary from two sequences if one is a tuple and the other is a list?

Yes! zip() works with any iterable sequences like lists, tuples, or strings.

beginner

Why is creating a dictionary from two sequences useful in programming?

It helps organize related data, like pairing names with phone numbers, making it easy to look up values by keys.

Which Python function pairs elements from two sequences to create key-value pairs?

A zip()

B map()

C filter()

D reduce()

zip() pairs elements from two sequences into tuples.

What does dict(zip(['x', 'y'], [10, 20, 30])) produce?

A {'x': 10, 'y': 20, None: 30}

B {'x': 10, 'y': 20}

C {'x': 10, 'y': 20, '': 30}

D Error due to length mismatch

zip() stops at the shortest sequence, so the extra 30 is ignored.

If you have keys = ('a', 'b') and values = [1, 2], how do you create a dictionary?

A keys + values

B dict(keys, values)

C zip(dict(keys), dict(values))

D dict(zip(keys, values))

Use dict(zip(keys, values)) to pair and convert to dictionary.

What type of object does zip() return in Python 3?

A An iterator of tuples

B A list of tuples

C A dictionary

D A tuple of lists

zip() returns an iterator that produces tuples.

Why might you prefer using dict(zip(keys, values)) over a for-loop to create a dictionary?

A It only works with lists

B It runs slower

C It is more concise and readable

D It creates a list instead

Using dict(zip()) is a clean, simple way to create dictionaries.

Explain how to create a dictionary from two sequences in Python.

Think about pairing elements and converting pairs into a dictionary.

What happens if the sequences used to create a dictionary have different lengths? How does Python handle this?

Consider how zip pairs elements one by one.