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

Posted by Ray1 B
Ray1 B
9,783 Points

.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
231,236 Points
Steven Parker
Steven Parker
231,236 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)
Ray1 B
Ray1 B
9,783 Points
Ray1 B
Ray1 B
9,783 Points

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.