go 23 lines · 6 steps

Multi-key sorting in Go

A single comparator chains four tie-breaking rules to sort employees by department, salary, and name.

Explained by highlit
Intermediate sorting comparators tie-breaking in-place
1type Employee struct {
2 Department string
3 LastName string
4 FirstName string
5 Salary int
6}
7 
8func sortEmployees(employees []Employee) {
9 sort.Slice(employees, func(i, j int) bool {
10 a, b := employees[i], employees[j]
11 
12 if a.Department != b.Department {
13 return a.Department < b.Department
14 }
15 if a.Salary != b.Salary {
16 return a.Salary > b.Salary
17 }
18 if a.LastName != b.LastName {
19 return a.LastName < b.LastName
20 }
21 return a.FirstName < b.FirstName
22 })
23}
01 / 01
STEP 01

Walkthrough

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Three takeaways
  1. 1A single less function can encode any number of sort keys by falling through to the next comparison only when values are equal.
  2. 2Direction is per-field: use less-than for ascending order and greater-than to sort a key like salary descending.
  3. 3sort.Slice reorders the slice in place, so the caller sees the sorted result without a return value.

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