Learning Python: Weird things about list

y = []  # declaring a constructor. This is equivalent to y = list()
y.append('book') #append book into the list
print y
y.append('pen')  #append pen into the list
y.append('pencil') #append pencil into the list
print y
print y.sort()  #I thought this would print the list but nope. It prints None
print y
t = y.sort() # doesn'tsort on the fly, it read the y = []
print t
y.sort()
print y



f = [1,2,'a','b']
f.sort()

print f

['book']

['book', 'pen', 'pencil']

None

['book', 'pen', 'pencil']

None

['book', 'pen', 'pencil']
[1, 2, 'a', 'b']

Just to look at things line by line

>>> y.append('book') #append book into the list

>>> print y

['book']



>>> y.append('pen')  #append pen into the list

>>> y.append('pencil') #append pencil into the list

>>> print y

['book', 'pen', 'pencil']





>>> print y.sort()  #I thought this would print the list but nope. It prints None

None



>>> print y

['book', 'pen', 'pencil']



>>> t = y.sort() # doesn'tsort on the fly, it read the y = []

>>> print t

None



>>> y.sort()

>>> print y

['book', 'pen', 'pencil']



>>> f = [1,2,'a','b']

>>> f.sort()



>>> print f

[1, 2, 'a', 'b']