Source code

x = {'a': 1, 'b': 2, 'd': 3, 'c' : 4}
d = list (x.keys ())
for key in sorted (d):
  print (key + '= & gt;' + d [key])

Error

Traceback (most recent call last):
 File "C: / Python projects / qq.py", line 4, in & lt; module & gt;
  print (key + '= & gt;' + d [key])
TypeError: list indices must be integers or slices, not str

Reading Mark Lutz – Python, 5th Edition and ran into a little problem. I’m using python 3.6.

Answer 1, authority 100%

There is a suspicion that there should be x [key] , not d [key] , otherwise the code doesn’t make much sense.

Answer 2, authority 100%

In the variable d , you have a list. List items are accessed by numeric index. For example d [0] . But in the loop variable key you have not numbers, but letters – a, b, c and d.