How to replace elements in a list using dictionary lookup

Given this list

my_lst = ['LAC', 'HOU', '03/03 06:11 PM', '2.13', '1.80', '03/03 03:42 PM']

I want to change its 0th and 1st values according to the dictionary value:

def translate(my_lst):
    subs = {
        "Houston": "HOU", 
        "L.A. Clippers": "LAC",

    }

so the list becomes:

['L.A. Clippers', 'Houston', '03/03 06:11 PM', '2.13', '1.80', '03/03 03:42 PM']

Solution

If all values are unique then you should reverse the dict first to get an efficient solution:

>>> subs = {
...         "Houston": "HOU", 
...         "L.A. Clippers": "LAC",
... 
...     }
>>> rev_subs = { v:k for k, v in subs.items()} # subs.iteritems() In Python 3
>>> [rev_subs.get(item, item)  for item in my_lst]
['L.A. Clippers', 'Houston', '03/03 06:11 PM', '2.13', '1.80', '03/03 03:42 PM']

If you're only trying to update selected indexes, then try:

indexes = [0, 1]
for ind in indexes:
    val =  my_lst[ind]
    my_lst[ind] = rev_subs.get(val, val)