In the context of this exercise, does the character being replaced in the
.replace() method have to be nonempty?
No, the character being replaced in the
.replace() method does not have to be a nonempty string, and can be the empty string
When providing an empty string as the argument for the character to be replaced, this will essentially replace every part between characters in the string. One way you can look at this, is as though every nonempty character has two empty spaces around it, which can overlap with their adjacent characters.
Here is an example that might help to illustrate this more clearly
empty_string = '' replaced = empty_string.replace('', '!!!') print(replaced) # !!! example_string = "code" result = example_string.replace('', '==') print(result) # ==c==o==d==e==