Swap values in a tuple/list inside a list in python?

Question

I have a tuple/list inside a list like this:

[(\'foo\',\'bar\'),(\'foo1\',\'bar1\'),(\'foofoo\',\'barbar\')]

What is the fastest way in pyt

Answer 1

You could use map:

map (lambda t: (t[1], t[0]), mylist)

Or list comprehension:

[(t[1], t[0]) for t in mylist]

List comprehensions are preferred and supposedly much faster than map when lambda is needed, however note that list comprehension has a strict evaluation, that is it will be evaluated as soon as it gets bound to variable, if you're worried about memory consumption use a generator instead:

g = ((t[1], t[0]) for t in mylist)
#call when you need a value
g.next()

There are some more details here: Python List Comprehension Vs. Map