Iterators, `iter`, and `next` [ref]

Problem¶

• Obtain both values from an iterator over [10, 20].
• Read a default value after that iterator is exhausted.
• Consume an iterator over [1, 2] twice with list.
• Lazily map int across ["1", "2"], then consume the result.
• Catch StopIteration from an empty iterator.

Python solution¶

it = iter([10, 20])
next(it)  # 10
next(it)  # 20

next(it, "done")  # 'done'

it = iter([1, 2])
list(it)  # [1, 2]
list(it)  # []

values = map(int, ["1", "2"])
list(values)  # [1, 2]

try:
    next(iter([]))
except StopIteration:
    exhausted = True
exhausted  # True

Links¶

• 295. Serialize and Deserialize Binary Tree (Top Medium)
• 341. Flatten Nested List Iterator (Top Hard)
• 179. Largest Number (Top Hard)
• 934. Shortest Bridge (Graph Theory)