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Go to latest Published: Aug 19, 2026 License: BSD-3-ClauseThe Go module system was introduced in Go 1.11 and is the official dependency management solution for Go.
Redistributable licenses place minimal restrictions on how software can be used, modified, and redistributed.
Modules with tagged versions give importers more predictable builds.
When a project reaches major version v1 it is considered stable.
Package cmp provides types and functions related to comparing ordered values.
This section is empty.
This section is empty.
Compare returns
-1 if x is less than y, 0 if x equals y, +1 if x is greater than y.
For floating-point types, a NaN is considered less than any non-NaN, a NaN is considered equal to a NaN, and -0.0 is equal to 0.0.
Example
package main
import (
"cmp"
"fmt"
"math"
)
func main() {
fmt.Println(cmp.Compare(1, 2))
fmt.Println(cmp.Compare("a", "aa"))
fmt.Println(cmp.Compare(1.5, 1.5))
fmt.Println(cmp.Compare(math.NaN(), 1.0))
}
Output: -1 -1 0 -1
Less reports whether x is less than y. For floating-point types, a NaN is considered less than any non-NaN, and -0.0 is not less than (is equal to) 0.0.
Example
package main
import (
"cmp"
"fmt"
"math"
)
func main() {
fmt.Println(cmp.Less(1, 2))
fmt.Println(cmp.Less("a", "aa"))
fmt.Println(cmp.Less(1.0, math.NaN()))
fmt.Println(cmp.Less(math.NaN(), 1.0))
}
Output: true true false true
func Or[T comparable](vals ...T) T
Or returns the first of its arguments that is not equal to the zero value. If no argument is non-zero, it returns the zero value.
Example
package main
import (
"cmp"
"fmt"
)
func main() {
// Suppose we have some user input
// that may or may not be an empty string
userInput1 := ""
userInput2 := "some text"
fmt.Println(cmp.Or(userInput1, "default"))
fmt.Println(cmp.Or(userInput2, "default"))
fmt.Println(cmp.Or(userInput1, userInput2, "default"))
}
Output: default some text some text
package main
import (
"cmp"
"fmt"
"slices"
"strings"
)
func main() {
type Order struct {
Product string
Customer string
Price float64
}
orders := []Order{
{"foo", "alice", 1.00},
{"bar", "bob", 3.00},
{"baz", "carol", 4.00},
{"foo", "alice", 2.00},
{"bar", "carol", 1.00},
{"foo", "bob", 4.00},
}
// Sort by customer first, product second, and last by higher price
slices.SortFunc(orders, func(a, b Order) int {
return cmp.Or(
strings.Compare(a.Customer, b.Customer),
strings.Compare(a.Product, b.Product),
cmp.Compare(b.Price, a.Price),
)
})
for _, order := range orders {
fmt.Printf("%s %s %.2f\n", order.Product, order.Customer, order.Price)
}
}
Output: foo alice 2.00 foo alice 1.00 bar bob 3.00 foo bob 4.00 bar carol 1.00 baz carol 4.00
type Ordered interface {
~int | ~int8 | ~int16 | ~int32 | ~int64 |
~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
~float32 | ~float64 |
~string
}
Ordered is a constraint that permits any ordered type: any type that supports the operators < <= >= >. If future releases of Go add new ordered types, this constraint will be modified to include them.
Note that floating-point types may contain NaN ("not-a-number") values. An operator such as == or < will always report false when comparing a NaN value with any other value, NaN or not. See the Compare function for a consistent way to compare NaN values.
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