# Reset Dropdown default values

**URL:** <https://community.plotly.com/t/reset-dropdown-default-values/8846>\
**Category:** Dash Python\
**Created:** [March 8, 2018, 12:27pm UTC](https://community.plotly.com/t/reset-dropdown-default-values/8846 "2018-03-08T12:27:33Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![gaurav13](https://avatars.discourse-cdn.com/v4/letter/g/4491bb/32.png) [@gaurav13](https://community.plotly.com/u/gaurav13)\
**Post date:** [March 8, 2018, 12:27pm UTC](https://community.plotly.com/t/reset-dropdown-default-values/8846/1 "2018-03-08T12:27:34Z")

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hi Team,

Could you please help - I was trying to empty the selection in dropdown (planning to do this for multiple dropdowns) values at a button click but this does’t seems to be working.  
 ![Capture](https://us1.discourse-cdn.com/flex024/uploads/plot/original/2X/8/8ed4b916f08f9531aabbbdb69ec16d9901bdef0e.JPG)

### Reset Filter values

@app.callback(dash.dependencies.Output(‘filterByN1’, ‘value’),  
[dash.dependencies.Input(‘resetButton’, ‘n\_clicks’)])  
def on\_click(n\_clicks):  
if (n\_clicks):  
return {‘value’:None}

Above snippet is replacing all selected values within a dropdown to Nan value as displayed in above image.

regards,

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**Author:** ![chriddyp](https://sea2.discourse-cdn.com/flex024/user_avatar/community.plotly.com/chriddyp/32/16855_2.png) [@chriddyp](https://community.plotly.com/u/chriddyp)\
**Post date:** [March 21, 2018, 1:14pm UTC](https://community.plotly.com/t/reset-dropdown-default-values/8846/2 "2018-03-21T13:14:34Z")

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> [@gaurav13](#):
>
> return {‘value’:None}

This isn’t the right Dash syntax. Where did you find this example? (Just so that we’re not misdocumenting this anywhere!). It should just be `return None`

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<div class="post-metadata">

**Author:** ![gaurav13](https://avatars.discourse-cdn.com/v4/letter/g/4491bb/32.png) [@gaurav13](https://community.plotly.com/u/gaurav13)\
**Post date:** [March 28, 2018, 1:18pm UTC](https://community.plotly.com/t/reset-dropdown-default-values/8846/3 "2018-03-28T13:18:52Z")

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Don’t have the reference link now but have seen this in some of the examples in forum.

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<div class="post-metadata">

**Author:** ![chriddyp](https://sea2.discourse-cdn.com/flex024/user_avatar/community.plotly.com/chriddyp/32/16855_2.png) [@chriddyp](https://community.plotly.com/u/chriddyp)\
**Post date:** [March 28, 2018, 4:50pm UTC](https://community.plotly.com/t/reset-dropdown-default-values/8846/4 "2018-03-28T16:50:04Z")

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OK. If you can find out where, please let us know. We don’t want things to be misdocumented!