random iteration in Python

Here's a different approach to iterating a list in random order. This doesn't modify the original list unlike the solutions that use shuffle()

lst=['a','b','c','d','e','f']
for value in sorted(lst,key=lambda _: random.random()):
    print value

or:

for value in random.sample(lst,len(lst)):
    print value

You can use random.shuffle() to, well, shuffle a list:

import random

r = list(range(1000))
random.shuffle(r)
for i in r:
  # do something with i

By the way, in many cases where you'd use a for loop over a range of integers in other programming languages, you can directly describe the "thing" you want to iterate in Python.
For example, if you want to use the values of i to access elements of a list, you should better shuffle the list directly:

lst = [1970, 1991, 2012]
random.shuffle(lst)
for x in lst:
  print x

NOTE: You should bear the following warning in mind when using random.shuffle() (taken from the docs:

Note that for even rather small len(x), the total number of permutations of x is larger than the period of most random number generators; this implies that most permutations of a long sequence can never be generated.

People often miss opportunities for modularization. You can define a function to encapsulate the idea of "iterate randomly":

def randomly(seq):
    shuffled = list(seq)
    random.shuffle(shuffled)
    return iter(shuffled)

then:

for i in randomly(range(1000)):
    #.. we're good to go ..