Merge pull request #2 from samber/feat-parallel

Adding lop.Map and lop.ForEach
samber · Mar 3, 2022 · def4dff · def4dff
2 parents 50e56b1 + 2566a93
commit def4dff
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## 1.2.0 (2022-03-03)
+
+Adding `lop.Map` and `lop.ForEach`.
+
 ## 1.1.0 (2022-03-03)
 
 Adding `i int` param to `lo.Map()`, `lo.Filter()`, `lo.ForEach()` and `lo.Reduce()` predicates.

diff --git a/Makefile b/Makefile
@@ -7,15 +7,15 @@ go1.18beta1:
 	go1.18beta1 download
 
 build:
-	${BIN} build -v .
+	${BIN} build -v ./...
 
 test:
-	go test -v .
-watch-test: tools
-	reflex -R assets.go -t 50ms -s -- sh -c 'gotest -v .'
+	go test -v ./...
+watch-test:
+	reflex -R assets.go -t 50ms -s -- sh -c 'gotest -v ./...'
 
 bench:
-	gotest -benchmem -bench .
+	gotest -benchmem -bench ./...
 
 coverage:
 	${BIN} test -v -coverprofile cover.out .

diff --git a/README.md b/README.md
@@ -27,7 +27,10 @@ go get github.com/samber/lo
 You can import `lo` using a basic statement:
 
 ```go
-import "github.com/samber/lo"
+import (
+    "github.com/samber/lo"
+    lop "github.com/samber/lo/parallel"
+)
 ```
 
 Then use one of the helpers below:
@@ -101,12 +104,25 @@ Constraints:
 Manipulates a slice and transforms it to a slice of another type:
 
 ```go
+import "github.com/samber/lo"
+
 lo.Map[int64, string]([]int64{1, 2, 3, 4}, func(x int64, _ int) string {
     return strconv.FormatInt(x, 10)
 })
 // []string{"1", "2", "3", "4"}
 ```
 
+Parallel processing: like lo.Map(), but mapper is called in goroutine. Results are returns in the same order.
+
+```go
+import lop "github.com/samber/lo/parallel"
+
+lop.Map[int64, string]([]int64{1, 2, 3, 4}, func(x int64, _ int) string {
+    return strconv.FormatInt(x, 10)
+}, 2)
+// []string{"1", "2", "3", "4"}
+```
+
 ### Filter
 
 Iterates over elements of collection, returning an array of all elements predicate returns truthy for.
@@ -146,7 +162,18 @@ Iterates over elements of collection and invokes iteratee for each element.
 lo.ForEach[string]([]string{"hello", "world"}, func(x string, _ int) {
     println(x)
 })
-// prints "hello\nworld"
+// prints "hello\nworld\n"
+```
+
+Parallel processing: like lo.ForEach(), but callback is called in goroutine.
+
+```go
+import lop "github.com/samber/lo/parallel"
+
+lop.ForEach[string]([]string{"hello", "world"}, func(x string, _ int) {
+    println(x)
+})
+// prints "hello\nworld\n" or "world\nhello\n"
 ```
 
 ### Uniq

diff --git a/go.mod b/go.mod
@@ -5,10 +5,7 @@ go 1.18
 require github.com/stretchr/testify v1.7.0
 
 require (
-	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/kr/text v0.2.0 // indirect
-	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
+	github.com/davecgh/go-spew v1.1.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f // indirect
-	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
+	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c // indirect
 )
diff --git a/go.sum b/go.sum
@@ -1,21 +1,11 @@
-github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
-github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
-github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
-github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
-github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
-github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs=
-github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f h1:BLraFXnmrev5lT+xlilqcH8XK9/i0At2xKjWk4p6zsU=
-gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
-gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/parallel/slice.go b/parallel/slice.go
@@ -0,0 +1,45 @@
+package parallel
+
+import "sync"
+
+// Map manipulates a slice and transforms it to a slice of another type.
+// `iteratee` is call in parallel. Result keep the same order.
+func Map[T any, R any](collection []T, iteratee func(T, int) R) []R {
+	result := make([]R, len(collection))
+
+	var mu sync.Mutex
+	var wg sync.WaitGroup
+	wg.Add(len(collection))
+
+	for i, item := range collection {
+		go func (_item T, _i int) {
+			res := iteratee(_item, _i)
+
+			mu.Lock()
+			result[_i] = res
+			mu.Unlock()
+
+			wg.Done()
+		}(item, i)
+	}
+
+	wg.Wait()
+
+	return result
+}
+
+// ForEach iterates over elements of collection and invokes iteratee for each element.
+// `iteratee` is call in parallel.
+func ForEach[T any](collection []T, iteratee func(T, int)) {
+	var wg sync.WaitGroup
+	wg.Add(len(collection))
+
+	for i, item := range collection {
+		go func (_item T, _i int) {
+			iteratee(_item, _i)
+			wg.Done()
+		}(item, i)
+	}
+
+	wg.Wait()
+}
diff --git a/parallel/slice_test.go b/parallel/slice_test.go
@@ -0,0 +1,24 @@
+package parallel
+
+import (
+	"testing"
+	"strconv"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMap(t *testing.T) {
+	is := assert.New(t)
+
+	result1 := Map[int, string]([]int{1, 2, 3, 4}, func(x int, _ int) string {
+		return "Hello"
+	})
+	result2 := Map[int64, string]([]int64{1, 2, 3, 4}, func(x int64, _ int) string {
+		return strconv.FormatInt(x, 10)
+	})
+
+	is.Equal(len(result1), 4)
+	is.Equal(len(result2), 4)
+	is.Equal(result1, []string{"Hello", "Hello", "Hello", "Hello"})
+	is.Equal(result2, []string{"1", "2", "3", "4"})
+}