These Python questions come up for junior developer, data and automation roles. Read the answer, then write the code yourself - the free Learn Python course runs every example in your browser.
Data types
List vs tuple? A list is mutable (you can change it); a tuple is immutable. Use a tuple for fixed collections and as dictionary keys. See dictionaries.
What is a dictionary? An unordered-by-design mapping of keys to values, with fast lookup by key.
Mutable vs immutable? Lists, dicts and sets are mutable; strings, numbers and tuples are immutable - reassigning them makes a new object.
Control flow and functions
What does a function return by default? None, if there is no
return.
*args and **kwargs? They let a function take any number of positional and keyword arguments.
What is a list comprehension? A concise way to build a list:
[x*2 for x in nums if x > 0].
Common gotchas
Why not use a mutable default argument? def f(x, items=[]) reuses
the same list across calls - use None and create it inside.
== vs is? == compares values; is compares identity
(the same object in memory).
How does Python handle integers and division? / gives a float;
// is floor division.
Practise writing it
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