Challenge 2: Flash Fill on Full Names — Solution Walkthrough

1. A1:A4 = "Ada Lovelace", "Alan Turing", "Grace Hopper",
   "Katherine Johnson".
2. B1 = "Lovelace" (typed by hand, the surname from A1).
3. Click B2, press Ctrl+E (or start typing "Turing" and accept the
   grey preview suggestion with Enter).

Expected result:
  B1: Lovelace
  B2: Turing
  B3: Hopper
  B4: Johnson

Explanation:

From the single example "Ada Lovelace" -> "Lovelace", Flash Fill
infers a text rule along the lines of "take the text after the last
space in the corresponding cell in column A" — i.e. extract the
surname. It then reapplies that same rule to A2, A3, and A4 to
produce Turing, Hopper, and Johnson.

If row 5 were just "Madonna" (a single word, no space at all), the
inferred "text after the last space" rule has nothing to extract —
there is no space to split on. Flash Fill would most likely either
leave that row's suggestion blank, repeat "Madonna" unchanged, or
simply decline to suggest anything for that row, since the example
rule doesn't generalise to an input shaped differently from the one
example it learned from.

Notes:
- This is the core limitation this chapter's tip box warns about:
  Flash Fill's inferred rule is only as good as the one example (or
  few examples) it was shown, and an input that doesn't match that
  shape can silently break the pattern rather than raising an error.
- Always scan a few extra rows after accepting a Flash Fill result —
  it will not tell you if row 37 didn't fit the rule it guessed.