What is Dict and List comprehensions are?

In Python, list comprehensions and dictionary comprehensions are a concise way to create lists and dictionaries, respectively, using a single line of code.

List comprehensions have the following syntax

Here, expression is the operation to be performed on each item in the iterable, item is the variable used to represent each item in the iterable, iterable is the sequence of items to be operated on, and condition is an optional expression that filters which items to include in the resulting list.

For example, the following list comprehension creates a list of even numbers between 0 and 9:

Dictionary comprehensions have a similar syntax, but use curly braces instead of square brackets, and include both a key and a value expression separated by a colon:

Here, key_expression and value_expression are expressions to be evaluated for each item in the iterable, and the resulting key-value pairs are used to create a dictionary.

For example, the following dictionary comprehension creates a dictionary of the squares of numbers between 1 and 5:

Using list and dictionary comprehensions can make your code more concise and easier to read, especially when you need to create a new list or dictionary based on an existing collection of data.