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-# select-video
+# Select video
+
+*author: Chen Zhang*
+
+
+<br />
+
+
+
+## Description
+
+This operator select input list by simply aggregating, sorting and then filtering it.
+<br />
+
+
+## Code Example
+
+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
+
+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()
+```
+
+![](mean.png)   
+
+```python
+import towhee
+
+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()
+```  
+![](mean.png) 
+
+```python
+import towhee
+
+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()
+```
+
+![](max.png) 
+
+
+```python
+import towhee
+
+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()
+```
+
+![](min.png) 
+
+
+<br />
+
+
+
+## Factory Constructor
+
+Create the operator via the following factory method
+
+***select_video(top_k: int, reduce_function: str, reverse: bool)***
+
+**Parameters:**
+
+​   ***top_k:*** *int*
+
+​   Select top k result.
+
+
+​   ***reduce_function:*** *str*
+
+​   Aggregate function name, support name:
+- sum
+- mean
+- max
+- min
+
+​   ***reverse:*** *bool*
+
+​   Whether sorted result is reversed.
+
+<br />
+
+
+
+## Interface
+
+
+**Parameters:**
+
+​	***video_urls:*** *List[str]*
+
+​  Video urls.
+
+​	***scores:*** *List[float]*
+
+​  Every video scores.
+
+
+**Returns:** *List[str]*
+
+​   Selected video url results.
+
+
 
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