sequence
An iterable which supports efficient element access using integer indices via the __getitem__()
special method and defines a __len__()
method that returns the length of the sequence. Some built-in sequence types are list
, str
, tuple
, and bytes
. Note that dict
also supports __getitem__()
and __len__()
, but is considered a mapping rather than a sequence because the lookups use arbitrary immutable keys rather than integers.
The collections.abc.Sequence
abstract base class defines a much richer interface that goes beyond just __getitem__()
and __len__()
, adding count()
, index()
, __contains__()
, and __reversed__()
. Types that implement this expanded interface can be registered explicitly using register()
.