diff --git a/package/PikaStdLib/PikaStdData.pyi b/package/PikaStdLib/PikaStdData.pyi
index a4360a32d..f5b553146 100644
--- a/package/PikaStdLib/PikaStdData.pyi
+++ b/package/PikaStdLib/PikaStdData.pyi
@@ -20,6 +20,9 @@ class Tuple:
     def __str__(self) -> str: ...
     def __len__(self) -> int: ...
 
+    def __contains__(self, val: any) -> int:
+        """ support val in list """
+
 
 class List(Tuple):
     def __init__(self): ...
@@ -41,9 +44,6 @@ class List(Tuple):
     def __add__(self, others: List) -> List:
         """ support list + list"""
 
-    def __contains__(self, val: any) -> int:
-        """ support val in list """
-
 
 class Dict:
     def __init__(self): ...
@@ -64,6 +64,9 @@ class Dict:
     def keys(self) -> dict_keys: ...
     def __len__(self) -> int: ...
 
+    def __contains__(self, val: any) -> int:
+        """ support val in list """
+
 
 class dict_keys:
     def __iter__(self) -> any: ...
diff --git a/package/PikaStdLib/PikaStdData_Dict.c b/package/PikaStdLib/PikaStdData_Dict.c
index 4d17ef125..cfe96a3c7 100644
--- a/package/PikaStdLib/PikaStdData_Dict.c
+++ b/package/PikaStdLib/PikaStdData_Dict.c
@@ -172,3 +172,23 @@ int PikaStdData_dict_keys___len__(PikaObj* self) {
     PikaDict* keys = obj_getPtr(dictptr, "_keys");
     return args_getSize(&keys->super);
 }
+
+int dict_contains(PikaDict* dict, Arg* key) {
+    int i = 0;
+    while (PIKA_TRUE) {
+        Arg* item = args_getArgByidex(&dict->super, i);
+        if (NULL == item) {
+            break;
+        }
+        if (arg_isEqual(item, key)) {
+            return PIKA_TRUE;
+        }
+        i++;
+    }
+    return PIKA_FALSE;
+}
+
+int PikaStdData_Dict___contains__(PikaObj *self, Arg* val){
+    PikaDict* dict = obj_getPtr(self, "_keys");
+    return dict_contains(dict, val);
+}
diff --git a/package/PikaStdLib/PikaStdData_List.c b/package/PikaStdLib/PikaStdData_List.c
index 1cd169049..877de58ff 100644
--- a/package/PikaStdLib/PikaStdData_List.c
+++ b/package/PikaStdLib/PikaStdData_List.c
@@ -77,14 +77,3 @@ PikaObj* PikaStdData_List___add__(PikaObj* self, PikaObj* others) {
     }
     return res;
 }
-
-int PikaStdData_List___contains__(PikaObj* self, Arg* val) {
-    PikaList* list = obj_getPtr(self, "list");
-    for (size_t i = 0; i < list_getSize(list); i++) {
-        Arg* arg = list_getArg(list, i);
-        if (arg_isEqual(arg, val)) {
-            return 1;
-        }
-    }
-    return 0;
-}
diff --git a/package/PikaStdLib/PikaStdData_Tuple.c b/package/PikaStdLib/PikaStdData_Tuple.c
index 1684ef069..d2ac01b8b 100644
--- a/package/PikaStdLib/PikaStdData_Tuple.c
+++ b/package/PikaStdLib/PikaStdData_Tuple.c
@@ -74,3 +74,14 @@ char* PikaStdData_Tuple___str__(PikaObj* self) {
 int PikaStdData_Tuple___len__(PikaObj* self) {
     return PikaStdData_Tuple_len(self);
 }
+
+int PikaStdData_Tuple___contains__(PikaObj* self, Arg* val) {
+    PikaList* list = obj_getPtr(self, "list");
+    for (size_t i = 0; i < list_getSize(list); i++) {
+        Arg* arg = list_getArg(list, i);
+        if (arg_isEqual(arg, val)) {
+            return 1;
+        }
+    }
+    return 0;
+}
diff --git a/port/linux/.vscode/launch.json b/port/linux/.vscode/launch.json
index 95d49ec18..14e46a4f9 100644
--- a/port/linux/.vscode/launch.json
+++ b/port/linux/.vscode/launch.json
@@ -11,7 +11,7 @@
             "program": "${workspaceFolder}/build/test/pikascript_test",
             // "program": "${workspaceFolder}/build/boot/demo06-pikamain/pikascript_demo06-pikamain",
             "args": [
-                // "--gtest_filter=re.search"
+                "--gtest_filter=dict.in"
             ],
             "stopAtEntry": false,
             "cwd": "${workspaceFolder}",
diff --git a/port/linux/.vscode/settings.json b/port/linux/.vscode/settings.json
index 98631d636..f6febba16 100644
--- a/port/linux/.vscode/settings.json
+++ b/port/linux/.vscode/settings.json
@@ -18,6 +18,7 @@
         "inet.h": "c",
         "re.h": "c",
         "cre.h": "c",
-        "pcre.h": "c"
+        "pcre.h": "c",
+        "pikastddata_dict.h": "c"
     }
 }
\ No newline at end of file
diff --git a/port/linux/package/pikascript/PikaStdData.pyi b/port/linux/package/pikascript/PikaStdData.pyi
index a4360a32d..f5b553146 100644
--- a/port/linux/package/pikascript/PikaStdData.pyi
+++ b/port/linux/package/pikascript/PikaStdData.pyi
@@ -20,6 +20,9 @@ class Tuple:
     def __str__(self) -> str: ...
     def __len__(self) -> int: ...
 
+    def __contains__(self, val: any) -> int:
+        """ support val in list """
+
 
 class List(Tuple):
     def __init__(self): ...
@@ -41,9 +44,6 @@ class List(Tuple):
     def __add__(self, others: List) -> List:
         """ support list + list"""
 
-    def __contains__(self, val: any) -> int:
-        """ support val in list """
-
 
 class Dict:
     def __init__(self): ...
@@ -64,6 +64,9 @@ class Dict:
     def keys(self) -> dict_keys: ...
     def __len__(self) -> int: ...
 
+    def __contains__(self, val: any) -> int:
+        """ support val in list """
+
 
 class dict_keys:
     def __iter__(self) -> any: ...
diff --git a/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_Dict.c b/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_Dict.c
index 4d17ef125..cfe96a3c7 100644
--- a/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_Dict.c
+++ b/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_Dict.c
@@ -172,3 +172,23 @@ int PikaStdData_dict_keys___len__(PikaObj* self) {
     PikaDict* keys = obj_getPtr(dictptr, "_keys");
     return args_getSize(&keys->super);
 }
+
+int dict_contains(PikaDict* dict, Arg* key) {
+    int i = 0;
+    while (PIKA_TRUE) {
+        Arg* item = args_getArgByidex(&dict->super, i);
+        if (NULL == item) {
+            break;
+        }
+        if (arg_isEqual(item, key)) {
+            return PIKA_TRUE;
+        }
+        i++;
+    }
+    return PIKA_FALSE;
+}
+
+int PikaStdData_Dict___contains__(PikaObj *self, Arg* val){
+    PikaDict* dict = obj_getPtr(self, "_keys");
+    return dict_contains(dict, val);
+}
diff --git a/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_List.c b/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_List.c
index 1cd169049..877de58ff 100644
--- a/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_List.c
+++ b/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_List.c
@@ -77,14 +77,3 @@ PikaObj* PikaStdData_List___add__(PikaObj* self, PikaObj* others) {
     }
     return res;
 }
-
-int PikaStdData_List___contains__(PikaObj* self, Arg* val) {
-    PikaList* list = obj_getPtr(self, "list");
-    for (size_t i = 0; i < list_getSize(list); i++) {
-        Arg* arg = list_getArg(list, i);
-        if (arg_isEqual(arg, val)) {
-            return 1;
-        }
-    }
-    return 0;
-}
diff --git a/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_Tuple.c b/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_Tuple.c
index 1684ef069..d2ac01b8b 100644
--- a/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_Tuple.c
+++ b/port/linux/package/pikascript/pikascript-lib/PikaStdLib/PikaStdData_Tuple.c
@@ -74,3 +74,14 @@ char* PikaStdData_Tuple___str__(PikaObj* self) {
 int PikaStdData_Tuple___len__(PikaObj* self) {
     return PikaStdData_Tuple_len(self);
 }
+
+int PikaStdData_Tuple___contains__(PikaObj* self, Arg* val) {
+    PikaList* list = obj_getPtr(self, "list");
+    for (size_t i = 0; i < list_getSize(list); i++) {
+        Arg* arg = list_getArg(list, i);
+        if (arg_isEqual(arg, val)) {
+            return 1;
+        }
+    }
+    return 0;
+}
diff --git a/port/linux/test/stddata-test.cpp b/port/linux/test/stddata-test.cpp
index 03bbd3125..db6ac7464 100644
--- a/port/linux/test/stddata-test.cpp
+++ b/port/linux/test/stddata-test.cpp
@@ -122,4 +122,24 @@ TEST(list, in){
     obj_deinit(pikaMain);
     EXPECT_EQ(pikaMemNow(), 0);
 }
+
+TEST(dict, in){
+    /* init */
+    pikaMemInfo.heapUsedMax = 0;
+    PikaObj* pikaMain = newRootObj("pikaMain", New_PikaMain);
+    /* run */
+    __platform_printf("BEGIN\r\n");
+    obj_run(pikaMain,
+            "if \"a\" in {\"a\":1, \"b\":2}:\n"
+            "    print('a in dict')\n"
+            );
+    /* collect */
+    /* assert */
+    EXPECT_STREQ(log_buff[0], "a in dict\r\n");
+    /* deinit */
+    obj_deinit(pikaMain);
+    EXPECT_EQ(pikaMemNow(), 0);
+}
+
+
 #endif
diff --git a/src/dataArg.c b/src/dataArg.c
index 674139083..074608878 100644
--- a/src/dataArg.c
+++ b/src/dataArg.c
@@ -458,18 +458,19 @@ PIKA_BOOL arg_isEqual(Arg* self, Arg* other) {
     if (arg_getType(self) != arg_getType(other)) {
         return PIKA_FALSE;
     }
-    if (arg_getContentSize(self) != arg_getContentSize(other)) {
-        return PIKA_FALSE;
-    }
     if (arg_getType(self) == ARG_TYPE_OBJECT) {
         if (arg_getPtr(self) != arg_getPtr(other)) {
             return PIKA_FALSE;
         }
-    } else {
-        if (0 != __platform_memcmp(arg_getContent(self), arg_getContent(other),
-                                   arg_getContentSize(self))) {
-            return PIKA_FALSE;
+    }
+    if (arg_getType(self) == ARG_TYPE_STRING){
+        if (strEqu(arg_getStr(self), arg_getStr(other))){
+            return PIKA_TRUE;
         }
     }
+    if (0 != __platform_memcmp(arg_getContent(self), arg_getContent(other),
+                               arg_getContentSize(self))) {
+        return PIKA_FALSE;
+    }
     return PIKA_TRUE;
 }