Simple syntax error in Python if else dict comprehension

Question

I have a set and dictionary and a value = 5

v = s = {\'a\', \'b\', \'c\'}
d = {\'b\':5 //<--new value}

If the key \'b\' in dictionary d

Answer 1

The expanded form of what you're trying to achieve is

a = {}
for k in v:
    a[k] = d[k] if k in d else 0

where d[k] if k in d else 0 is the Python's version of ternary operator. See? You need to drop k: from the right part of the expression:

{k: d[k] if k in d else 0 for k in v} # ≡ {k: (d[k] if k in d else 0) for k in v}

You can write it concisely like

a = {k: d.get(k, 0) for k in d}