Problem in understanding Python list comprehensions

Question

What does the last line mean in the following code?

import pickle, urllib                                                                                                 


        

Answer 1

Maybe best explained with an example:

print "".join([e[1] * e[0] for e in elt])

is the short form of

x = []
for e in elt:
  x.append(e[1] * e[0])
print "".join(x)

List comprehensions are simply syntactic sugar for for loops, which make an expression out of a sequence of statements.

elt can be an arbitrary object, since you load it from pickles, and e likewise. The usage suggests that is it a sequence type, but it could just be anything that implements the sequence protocol.