Question

How do I check whether an object supports [] operation in Python? I think of something like the following:

if supports(obj, ?[]?):
    print("Supports")  

Answer 1

Try hasattr(obj, "__getitem__"):

if hasattr(obj, "__getitem__"):
    print("Supports") 

From the operator.getitem help:

operator.getitem??
Type:           builtin_function_or_method
Base Class:     <type 'builtin_function_or_method'>
String Form:    <built-in function getitem>
Namespace:      Interactive
getitem(a, b) -- Same as a[b].

Check out the operator module:

• Return the value of a at index b:

  operator.getitem(a, b)
  operator.__getitem__(a, b)
  

• Return the slice of a from index b to index c-1:

  operator.getslice(a, b, c)
  operator.__getslice__(a, b, c)
  

• Set the value of a at index b to c:

  operator.setitem(a, b, c)
  operator.__setitem__(a, b, c)
  

• Set the slice of a from index b to index c-1 to the sequence v.

  operator.setslice(a, b, c, v)
  operator.__setslice__(a, b, c, v)
  

• Remove the value of a at index b:

  operator.delitem(a, b)
  operator.__delitem__(a, b)
  

• Delete the slice of a from index b to index c-1:

  operator.delslice(a, b, c)
  operator.__delslice__(a, b, c)
  

etc..