[Tutor] Using type

[Alan Gauld]

On 12/08/11 07:04, Emeka wrote:
> Hello All,
>
> I need help here, type(item) == [].__class__:. What is the idiomatic way
> of doing it?

if type(item) == type([])...

or in this case

if type(item) == list...

But probably preferrable to using type is to use isinstance:

if isinstance(item, list)...

And even more preferable still is don't check the type at
all but just try the operation

try:
    item.doSomething()
except AttributeError:
    doSomethingElse(item)


But that isn't always appropriate.

> def myflatten(my_data):
>    gut = []
>    for item in my_data:
>         if type(item) == [].__class__:
>          gut =  gut + myflatten ( item)
>         else:
>           gut.append(item)
>    return gut

In this particular case you presumably want to be
able to use any iterable object as an argument.
So it might be better written as:

def myflatten(my_data):
     gut = []
     for item in my_data:
        try:
           iter(item)  # test for iterability
           gut = gut + myflatten(item)
        except TypeError:
           gut.append(item)
      return gut


-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/