Function

def f(x):

no return will return None

Tuples元组

• an ordered sequence of elements, can mix element types
• immutable
  t = (2, "mit", 3)
  t[1] = 4 error

conveniently used to swap variable values: (x, y) = (y, x)

def f(x, y)
  a = x // y      //integer division
  b = x % y
return (a , b)

List

• lists are mutable
  L = [2, 'a', 4, [1,2]]
  len(L)=4

total = 0
for i in L:
  total +=i
print total

add elements: L.append(element)
convert string to list: list(s)
s.split('<')
''.join(L) to turn a list of characters into a string

• sort() and sorted()
  sorted does not mutate
  sort mutate, return nothing

colone a list: chill = cool[:]