diff --git a/cli.go b/cli.go
index 59caf51..47b54c2 100644
--- a/cli.go
+++ b/cli.go
@@ -14,6 +14,7 @@ type cliParser interface {
 	getCliArgs(startIndex, endIndex int) (args []string)
 	PrintVersion(specs []string)
 	PrintUsage()
+	FlagIsSet(flag int16) bool
 }
 
 type cliOptionParser interface {
@@ -41,20 +42,31 @@ type OptReference interface {
 	SetHidden(hidden bool)
 }
 
+const (
+	ResetOnEqualSign = int16(1 << iota) // for some option types, like arrays, the equal signs reset to empty the accumulator of values
+)
+
 type CliParser struct {
 	description string
 	version     string
 	options     []cliOptionParser
 	argSpecs    []argSpec
 	cliArgs     []string
+	flags       int16
 }
 
-func (cli *CliParser) Init(argv []string, version string, description string) {
+func (cli *CliParser) Init(argv []string, version string, description string, flags ...int16) {
 	cli.version = version
 	cli.description = description
 	cli.cliArgs = argv
+	for _, flag := range flags {
+		cli.flags |= flag
+	}
 }
 
+func (cli *CliParser) FlagIsSet(flag int16) bool {
+	return (cli.flags & flag) == flag
+}
 func (cli *CliParser) GetOption(name string) (ref OptReference) {
 	var opt cliOptionParser
 	if strings.HasPrefix(name, "-") {
diff --git a/opt-int-array.go b/opt-int-array.go
index 5975627..2507611 100644
--- a/opt-int-array.go
+++ b/opt-int-array.go
@@ -75,7 +75,7 @@ func (opt *cliOptionIntArray) parse(parser cliParser, argIndex int, valuePtr *st
 						err = errInvalidOptionValue(opt.name, boxedValue, "num-array")
 					}
 				} else {
-					if !opt.alreadySeen {
+					if !opt.alreadySeen || (valuePtr != nil && parser.FlagIsSet(ResetOnEqualSign)) {
 						*opt.targetVar = []int{}
 						opt.alreadySeen = true
 					}
diff --git a/opt_test.go b/opt_test.go
index ce7555f..473c034 100644
--- a/opt_test.go
+++ b/opt_test.go
@@ -49,12 +49,12 @@ func addBoxOption(cli *CliParser, boxPtr *[]int) {
 	})
 }
 
-func testIntArrayOptOk(t *testing.T, n int, args []string) {
+func testIntArrayOptOk(t *testing.T, n int, args []string, flags ...int16) {
 	var box []int
 	var cli CliParser
 	t.Logf("Arg set n. %d", n)
 	addBoxOption(&cli, &box)
-	cli.Init(args, "1.0.0", "TestIntArrayOpt description")
+	cli.Init(args, "1.0.0", "TestIntArrayOpt description", flags...)
 	if err := cli.Parse(); err != nil {
 		t.Error(err)
 	} else if len(box) != 4 {
@@ -62,12 +62,12 @@ func testIntArrayOptOk(t *testing.T, n int, args []string) {
 	}
 }
 
-func testIntArrayOptKo(t *testing.T, n int, args []string, msg string) {
+func testIntArrayOptKo(t *testing.T, n int, args []string, msg string, flags ...int16) {
 	var box []int
 	var cli CliParser
 	t.Logf("Arg set n. %d", n)
 	addBoxOption(&cli, &box)
-	cli.Init(args, "1.0.0", "TestIntArrayOpt description")
+	cli.Init(args, "1.0.0", "TestIntArrayOpt description", flags...)
 	if err := cli.Parse(); err == nil {
 		t.Errorf("Expected error, got nil")
 	} else if err.Error() != msg {
@@ -132,4 +132,12 @@ func TestIntArrayOpt(t *testing.T) {
 		"--box", "450,12",
 	}
 	testIntArrayOptKo(t, n, args, "--box option requires exactly 4 items, 5 provided")
+
+	n++
+	args = []string{
+		"TestIntArrayOpt",
+		"--box", "100,200,150",
+		"--box=100,200,150,450",
+	}
+	testIntArrayOptOk(t, n, args, ResetOnEqualSign)
 }