# Reverse of group function **URL:** \ **Category:** Community Support\ **Tags:** kdb-and-q\ **Created:** [November 29, 2016, 7:51pm UTC](https://forum.kx.com/t/reverse-of-group-function/11403 "2016-11-29T19:51:00Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![evd](https://avatars.discourse-cdn.com/v4/letter/e/e274bd/32.png) [@evd](https://forum.kx.com/u/evd)\ **Post date:** [November 29, 2016, 7:51pm UTC](https://forum.kx.com/t/reverse-of-group-function/11403/1 "2016-11-29T19:51:00Z")
q) di:group li:1 2 3 3 2 1 1| 0 5 2| 1 4 3| 2 3 How having di get li? Is there better than {@[x;y;:;z]}/[(sum count each di)#0N;value di;key di] ? ---
**Author:** ![charlie1](https://avatars.discourse-cdn.com/v4/letter/c/ec9cab/32.png) [@charlie1](https://forum.kx.com/u/charlie1)\ **Post date:** [November 29, 2016, 8:14pm UTC](https://forum.kx.com/t/reverse-of-group-function/11403/2 "2016-11-29T20:14:00Z")
one way q)di:group li:10000000?10000 q)li~(where count each di)iasc raze di 1b q)\ts (where count each di)iasc raze di 1401 402784640 q)\ts {@[x;y;:;z]}/[(sum count each di)#0N;value di;key di]  121931 402670528 ---
**Author:** ![evd](https://avatars.discourse-cdn.com/v4/letter/e/e274bd/32.png) [@evd](https://forum.kx.com/u/evd)\ **Post date:** [November 29, 2016, 8:46pm UTC](https://forum.kx.com/t/reverse-of-group-function/11403/3 "2016-11-29T20:46:00Z")
It is great. I used to apply where function to binary lists and forgot his affect for integer lists and dictionaries. Thanks for reminding me. ---
**Author:** ![Attila](https://avatars.discourse-cdn.com/v4/letter/a/b9bd4f/32.png) [@Attila](https://forum.kx.com/u/Attila)\ **Post date:** [November 29, 2016, 10:47pm UTC](https://forum.kx.com/t/reverse-of-group-function/11403/4 "2016-11-29T22:47:00Z")
another way, ie amend can be okay if the over is avoided q)\ts (where count each di)iasc raze di 3440 402784576 q)\ts @[count[r]#first key di;r:raze di;:;where count each di] 497 402653840 >