diff --git a/README.md b/README.md
index d05c6f6..9d626f6 100644
--- a/README.md
+++ b/README.md
@@ -18,41 +18,57 @@ This operator select input list by simply aggregating, sorting and then filterin
 For two input lists: video urls and scores, aggregate url by reduce_function, then sort aggregated scores, then select top k results.
 
 ```python
-import towhee
+from towhee.dc2 import pipe, ops, DataCollection
 
-towhee.dc['video_urls', 'scores']([[['a', 'a', 'c', 'a', 'b', 'b', 'c', 'c'], [2, 8, 9.3, 5, 2, 1, 0, -1]]])\
-.video_copy_detection.select_video[('video_urls','scores'), 'res'](top_k=2, reduce_function='mean', reverse=True)\
-.show()
+p = (
+    pipe.input('video_urls', 'scores') \
+        .map(('video_urls', 'scores'), 'res', ops.video_copy_detection.select_video(top_k=2, reduce_function='mean', reverse=True)) \
+        .output('video_urls', 'scores', 'res')
+)
+
+DataCollection(p(['a', 'a', 'c', 'a', 'b', 'b', 'c', 'c'], [2, 8, 9.3, 5, 2, 1, 0, -1])).show()
 ```
 
 ![](mean.png)   
 
 ```python
-import towhee
+from towhee.dc2 import pipe, ops, DataCollection
+
+p = (
+    pipe.input('video_urls', 'scores') \
+        .map(('video_urls', 'scores'), 'res', ops.video_copy_detection.select_video(top_k=2, reduce_function='sum', reverse=True)) \
+        .output('video_urls', 'scores', 'res')
+)
 
-towhee.dc['video_urls', 'scores']([[['a', 'a', 'c', 'a', 'b', 'b', 'c', 'c'], [2, 8, 9.3, 5, 2, 1, 0, -1]]])\
-.video_copy_detection.select_video[('video_urls','scores'), 'res'](top_k=2, reduce_function='sum', reverse=True)\
-.show()
+DataCollection(p(['a', 'a', 'c', 'a', 'b', 'b', 'c', 'c'], [2, 8, 9.3, 5, 2, 1, 0, -1])).show()
 ```  
 ![](mean.png) 
 
 ```python
-import towhee
+from towhee.dc2 import pipe, ops, DataCollection
 
-towhee.dc['video_urls', 'scores']([[['a', 'a', 'c', 'a', 'b', 'b', 'c', 'c'], [2, 8, 9.3, 5, 2, 1, 0, -1]]])\
-.video_copy_detection.select_video[('video_urls','scores'), 'res'](top_k=2, reduce_function='max', reverse=True)\
-.show()
+p = (
+    pipe.input('video_urls', 'scores') \
+        .map(('video_urls', 'scores'), 'res', ops.video_copy_detection.select_video(top_k=2, reduce_function='max', reverse=True)) \
+        .output('video_urls', 'scores', 'res')
+)
+
+DataCollection(p(['a', 'a', 'c', 'a', 'b', 'b', 'c', 'c'], [2, 8, 9.3, 5, 2, 1, 0, -1])).show()
 ```
 
 ![](max.png) 
 
 
 ```python
-import towhee
+from towhee.dc2 import pipe, ops, DataCollection
+
+p = (
+    pipe.input('video_urls', 'scores') \
+        .map(('video_urls', 'scores'), 'res', ops.video_copy_detection.select_video(top_k=2, reduce_function='min', reverse=True)) \
+        .output('video_urls', 'scores', 'res')
+)
 
-towhee.dc['video_urls', 'scores']([[['a', 'a', 'c', 'a', 'b', 'b', 'c', 'c'], [2, 8, 9.3, 5, 2, 1, 0, -1]]])\
-.video_copy_detection.select_video[('video_urls','scores'), 'res'](top_k=2, reduce_function='min', reverse=True)\
-.show()
+DataCollection(p(['a', 'a', 'c', 'a', 'b', 'b', 'c', 'c'], [2, 8, 9.3, 5, 2, 1, 0, -1])).show()
 ```
 
 ![](min.png)