How to do structural pattern matching in Python 3.10 with a type to match?

Question

I am trying to match a type in Python 3.10 using the console:

t = 12.0
match type(t):
  case int:
    print("int")
  case float:
    print("float")

And I get this error:

  File "<stdin>", line 2
SyntaxError: name capture 'int' makes remaining patterns unreachable

How can I fix this issue?

Answer 1

Loose the type() and also add parentheses to your types:

t = 12.0
match t:
  case int():
    print("int")
  case float():
    print("float")

I'm not sure why what you've wrote is not working, but this one works.

Answer 2

My fix was:

match type(t):
  case v if v is int:
    print("int")
  case v if v is float:
    print("float")

It is not very elegant but it is the best I can do with pattern matching.

Answer 3

I think a more readable option instead of pattern matching is the following:

t = 12.0
if isinstance(t, int):
  print("int")
elif isinstance(t, float):
  print("float")