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#0209
Order Factor Levels in R
EasyR15 min10 XP
Problem
Given size labels small, medium, and large, create an ordered factor with that order.
Why This Matters
R often sorts text alphabetically unless factor levels tell it the meaningful order.
Examples
Example 1
Inputmedium, small, large, small
Outputordered levels: small < medium < large
The values keep their row order, but the factor levels now have a meaningful rank.
Constraints
- Return the exact requested result.
- Handle common edge cases.
- Keep the solution readable before optimizing.
CodeR
Visible browser tests run here when available.
Testcases1 visible / 3 hidden categories
Core example
Inputmedium, small, large, small
Expectedordered levels: small < medium < large
The values keep their row order, but the factor levels now have a meaningful rank.
Hidden Test Categories
empty or minimal inputrepeated valueslarger realistic input