2D List comprehension & replace

[Larry Bates]

I've gone brain-dead trying to get this to work
using list comprehensions.  I have a list of lists
like the following:

l=[[92.6, 0, 93.5],
   [94.7, 95.6, 95.7],
   [91.2, 92.1, 93.0]]

what I want is a new list
with the zero (0) replaced with None.

I thought I would use the fact that the command:

0 or None

seems to return None.

This procedural code does the trick, but I just
know it can be done with a single list comprehension.

tol=[]
for a in l:
    til=[]
    for v in a:
        if a != 0: til.append(v)
        else:      til.append(None)

    tol.append(til)

l=tol

Thanks in advance.

Larry Bates