Python: Replace All Values in a Dictionary

Sure, you can do something like:

d = {x: 1 for x in d}

That creates a new dictionary d that maps every key in d (the old one) to 1.

You can use a dict comprehension (as others have said) to create a new dictionary with the same keys as the old dictionary, or, if you need to do the whole thing in place:

for k in d:
    d[k] = 1

If you're really fond of 1-liners, you can do it in place using update:

d.update( (k,1) for k in d )