Sort An Array Of Hashes By Multiple Keys In Ruby
Sorting a collection of hashes by a single key is straightforward, but sorting by multiple keys — primary sort by one field, secondary sort by another — requires a slightly different approach using Ruby’s sort_by with an array of values.
Description
Ruby’s Enumerable#sort_by accepts an array as the sort key. Ruby compares arrays element by element, so [primary, secondary] sorts by primary first, then by secondary only when primary values are equal. This works for any number of sort keys and supports ascending and descending order per key using negation or reverse.
This is commonly needed when displaying sorted records — e.g., sort by status first, then by name alphabetically within each status group.
Sample input:
records = [
{ name: "Charlie", score: 90, level: 2 },
{ name: "Alice", score: 90, level: 1 },
{ name: "Bob", score: 85, level: 3 },
{ name: "Diana", score: 85, level: 1 }
]
Sample Output (sort by score desc, then name asc):
[
{ name: "Alice", score: 90, level: 1 },
{ name: "Charlie", score: 90, level: 2 },
{ name: "Bob", score: 85, level: 3 },
{ name: "Diana", score: 85, level: 1 }
]
Answer
# Sort by score descending, then name ascending
sorted = records.sort_by { |r| [-r[:score], r[:name]] }
# Sort by multiple keys in a reusable method
def multi_sort(array, *keys)
array.sort_by { |item| keys.map { |key, dir| dir == :desc ? -item[key] : item[key] rescue item[key] } }
end
# Example: sort by score desc, then level asc
sorted = records.sort_by { |r| [-r[:score], r[:level], r[:name]] }
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