Intro to Python for Computer Science and Data Science: Learning to Program with AI, Big Data and The Cloud

5.12 List Comprehensions

Here, we continue discussing functional-style features with list comprehensions—a concise and convenient notation for creating new lists. List comprehensions can replace many for statements that iterate over existing sequences and create new lists, such as:

In [1]: list1 = []

In [2]: for item in range(1, 6):
   ...:    list1.append(item)
   ...:

In [3]: list1
Out[3]: [1, 2, 3, 4, 5]

Using a List Comprehension to Create a List of Integers

We can accomplish the same task in a single line of code with a list comprehension:

In [4]: list2 = [item for item in range(1, 6)]

In [5]: list2
Out[5]: [1, 2, 3, 4, 5]

Like snippet [2]’s for statement, the list comprehension’s for clause

for item in range(1, 6)

iterates over the sequence ...