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Python Python Collections (2016, retired 2019) Sets Set Math

.symmetric_difference(other) or .symmetric_difference(*other) in Teachers Notes of Set Math in Python Collections?

Noticed the bottom of Teacher's Notes:

<also: notice how those are using *others? That's a tuple of other sets. See, I told you that pattern was everywhere!>

However,

^ or .symmetric_difference(other)

doesn't include a star. Is there a reason for this?

Thanks!

2 Answers

Steven Parker
Steven Parker
229,982 Points

They call that the "splat" operator.

As used here, it performs argument unpacking. So when you pass other by itself, it's just a single argument (which might be a list). But when you pass it as *other, then you are taking the list and converting it into individual arguments. For example:

blob = [1, 2, 3]
somefunction(blob)   # this passes the list "blob" as a single argument
somefunction(*blob)  # this is the same thing as: somefunction(1, 2, 3)

Ok thanks! I was just confused on why the other set operations in the Teachers Notes had a splat operator but this one didn't.