Sorting and deterministic tie rules

The idea

Sorting needs a clear ordering rule, especially when several records share the same primary value. sort_by can compute a compound key such as [score, name], making secondary ordering explicit. A nonbang sorting method returns a new outer array, while sort! changes the receiver. Neither operation automatically duplicates mutable objects stored inside that array.

A report should not depend on unspecified tie behavior when consistent ordering matters. Include a stable identifier or original index as a secondary key if the requirement needs it. Searching can also depend on ordering: a binary-search predicate must change monotonically across the input. For an unsorted collection, a linear find is appropriate unless the program first establishes and maintains the required sorted order.

records=[{score:2,name:"B"},{score:1,name:"C"},{score:2,name:"A"}]
ordered=records.sort_by { |r| [r[:score],r[:name]] }
puts ordered.map { |r| r[:name] }.join(",")

C,A,B

The lowest score comes first; equal scores are resolved alphabetically by the secondary key.