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Python Python Collections (Retired) Lists Redux Combining Lists

Joe di Stefano
Joe di Stefano
Courses Plus Student 5,533 Points

Is list() necessary?

At 1:38 the teacher writes the following to create a new list:

our_list = list(range(10))

Since range() returns a list, I don't see the purpose of using list() here. Am I missing something?

2 Answers

Stone Preston
Stone Preston
42,016 Points

in Python 3.x, the range() constructor returns a range sequence type, not a list like it did in Python 2.x. So yes the call to list() is necessary to convert the range to a list. See the Range documentation for more information

From the documentation:

The range type represents an immutable sequence of numbers and is commonly used for looping a specific number of times in for loops.

Kenneth Love
Kenneth Love
Treehouse Guest Teacher

Yep, almost nothing actually returns a list in Python 3. This is better behavior than Python 2's because now you can cast your range() or dict.keys() or whatever to whatever data type you actually want. One less step!