Find all the minimal values on a list

I have a list of tuples. Each tuple’s element 0 is a numeric value. I want to find all the tuples with the minimal value in element 0. For example:

l = [(2, 'a'), (1, 'b'), (3, 'c'), (1, 'd'), (4, 'e'), (1, 'f')]
l.sort()
i = 1
while i < len(l):
    if l[i - 1][0] != l[i][0]:
        break
i += 1
print(l[:i])

would give me what I want:

[(1, 'b'), (1, 'd'), (1, 'f')]

My question is (could be three different answers): what is the Code Golf/fastest/most Pythonic way to do this?

Answer

Here’s a solution using min. The time complexity is O(n) and it uses O(1) auxiliary space (i.e. not including the space for the output list).

from operator import itemgetter

min_key, _ = min(lst, key=itemgetter(0))
result = [ (k, v) for k, v in lst if k == min_key ]