C..1 list

>>> x=[]
>>> x
[]

>>> x=[1]
>>> x
[1]

>>> x=[1,'two']
>>> x
[1, 'two']
>>> x[0]
1
>>> x[1]
'two'

>>> x[1]=2
>>> x
[1, 2]

>>> x.append(3)
>>> x
[1, 2, 3]

append() 出来るのはいわゆるリストだからか。