Elegant way to convert list to hex string

python

Solution

Joining the one-liners club, by way of bit manipulation which seems more appropriate.

val = hex(reduce(lambda total, wall: total << 1 | wall, walls, 0))

This does the same as:

val = 0
for wall in walls:
    val <<= 1 # add one 0 bit at the "end"
    val |= wall # set this bit to 1 if wall is True, otherwise leave it at 0

val = hex(val) # get a hex string in the end
val = format(val, 'x') # or without the leading 0x if it's undesired

Problem

I have a long list that looks like this: ``` [True, True, True, False, ... ] ``` Representing walls in a tile map. It isn't guaranteed to be a multiple of 4 long, but it doesn't matter if it gets padded at the end. I'd like to convert this into a hex string, so for the above example it would start with E ... I was hoping there was a nice elegant way to do this (using Python 2.7.3)! Thanks. EDITED This is an example of a 9x9 map: ``` map = [True, True, True, True, True, True, True, True, True, True, True, True, True, False, False, True, True, True, True, True, True, False, False, False, False, True, True, True, True, True, False, False, False, False, True, True, True, True, True, True, False, False, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True, True]# False, False, False padded ``` what I would like is to be able to ``` str = heximify(map) print str > FFF9F87C3F3FFFFFFFFF8 ```

Original source