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Python Object-Oriented Python Advanced Objects Subclassing Built-ins

self[item] notation

I don't understand why we use the '[' brackets instead of the traditional one: '('. Anyone able to clarify it?

1 Answer

Greg Kaleka
Greg Kaleka
39,021 Points

Hi Stefano,

Brackets [] and parentheses () are used for completely different things in Python. There's also braces {}, which I won't get into, but those are used for other, completely different things.

In this video, Kenneth is using brackets because that's how you create slices. You may wish to review the section of the Python Collections course that covers slices. As a general rule, brackets are used when dealing with Python lists, or other iterables like strings (note slices are only applicable to iterables, hence the brackets). Parentheses are used for a number of things, but most notably defining and calling functions and types. They're also used to group mathematical operations - like (2 + 5) * 12, and grouping import statements and long if statements.

Hope that's helpful!

Cheers :beers: