Question

In Darius Bacon’s code, on the line 11 and 12, there is the following code:

prefixes = set(word[:i] for word in words for i in range(2, len(word)+1))

I’m trying to translate his program into Java and I’m having difficulties with this one.

What does this do?

Answer 1

Expanding the list comprehension:

prefixes = set()
for word in words:
    for i in range(2, len(word)+1)
        prefixes.add(word[:i])

word[:i] is word up to but not including index i