diff --git a/src/interpreter/primitive_props.rs b/src/interpreter/primitive_props.rs
index 560440d..0bb0028 100644
--- a/src/interpreter/primitive_props.rs
+++ b/src/interpreter/primitive_props.rs
@@ -277,14 +277,14 @@ pub fn get_prim_prop(target: Value, name: String) -> Result<Value, AiScriptError
                         .next()
                         .map(f64::try_from)
                         .map_or(Ok(None), |r| r.map(|i| Some(i as isize)))?
-                        .unwrap_or(0);
+                        .unwrap_or(target_len);
                     if raw_index < -target_len || target_len < raw_index {
                         return Ok(Value::bool(false));
                     }
                     let index = if raw_index >= 0 {
-                        target_len - raw_index
+                        raw_index
                     } else {
-                        -raw_index
+                        target_len + raw_index
                     } as usize;
 
                     Ok(Value::bool(
diff --git a/tests/test.rs b/tests/test.rs
index 54a7d49..2a1c0b7 100644
--- a/tests/test.rs
+++ b/tests/test.rs
@@ -3964,9 +3964,9 @@ mod primitive_props {
                 let str = "hello"
                 let empty = ""
                 <: [
-                    // str.ends_with("", 3), str.ends_with("lo", 5),
-                    // str.ends_with("ll", 4), str.ends_with("he", 2),
-                    // str.ends_with("ll", -1), str.ends_with("he", -3),
+                    str.ends_with("", 3), str.ends_with("lo", 5),
+                    str.ends_with("ll", 4), str.ends_with("he", 2),
+                    str.ends_with("ll", -1), str.ends_with("he", -3),
                     str.ends_with("he", 5), str.ends_with("lo", 3),
                     str.ends_with("lo", -6), str.ends_with("", -7),
                     str.ends_with("lo", 6), str.ends_with("", 7),
@@ -3977,12 +3977,12 @@ mod primitive_props {
                     assert_eq!(
                         res,
                         arr([
-                            // bool(true),
-                            // bool(true),
-                            // bool(true),
-                            // bool(true),
-                            // bool(true),
-                            // bool(true),
+                            bool(true),
+                            bool(true),
+                            bool(true),
+                            bool(true),
+                            bool(true),
+                            bool(true),
                             bool(false),
                             bool(false),
                             bool(false),