What is the equivalent of Scala's map case in Python

Question

In Scala, you could write expressions like

A.map{case (x, y) => (y, y)}

I was wondering, how we write the equivalent statement in Python?

Answer 1

I don't know Scala, so I have to guess a bit. This looks like you are mapping a function taking two arguments over a list of pairs, and replace each pair with two times the second element. In Python, you would use a list comprehension for this purpose:

[(y, y) for x, y in A]

The Scala function probably uses pattern matching to assign the value of x and y . Python doesn't have pattern matching, but in this simple case sequence unpacking achieves the same goal.