[Q] Type checking...go further...

[Michael P. Reilly]

Stidolph, David <stidolph at origin.ea.com> wrote:
: You cannot have typed method parameters (Python is typeless), but can only
: check the types of parameters within the method.

: from types import * #Needed for different types like IntType

: def foo(a, b, c):
:   if type(a) is IntType:
:     print a,'is a integer'
:   elif type(a) is LongType:
:     print a,'is a long integer'
:   elif type(a) is StringType:
:     print a,'is a integer'
:   elif type(a) is FloatType:
:     print a,'is a floating point number'
:   elif type(a) is ListType:
:     print a,'is a list'
:   elif type(a) is TupleType:
:     print a,'is a tuple'

: or

: def foo(a,b,c):
:   if not (type(a) is IntType):
:     raise "Param a must be integer"
:   if not (type(b) is StringType):
:     raise "Param b must be string"
:   if not (type(c) is ListType):
:     raise "Param c must be list"
:   ...

The "isinstance()" builtin function also works on types:

  def foo(a, b, c):
    if not isinstance(a, types.IntType):
      raise TypeError, "Param a must be integer"
    if not isinstance(b, types.StringType):
      raise TypeError, "Param b must be string"
    if not isinstance(c, types.ListType):
      raise TypeError, "Param c must be list"

It is often better not to call "from types import *" since that can
clutter the namespace unnecessarily.

  -Arcege