# How to create custom Expectations for pandas

**URL:** <https://discourse.greatexpectations.io/t/how-to-create-custom-expectations-for-pandas/201>\
**Category:** Archive\
**Tags:** how-to, help-wanted\
**Created:** [May 28, 2020, 1:58pm UTC](https://discourse.greatexpectations.io/t/how-to-create-custom-expectations-for-pandas/201 "2020-05-28T13:58:27Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![kyle](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.greatexpectations.io/kyle/32/18_2.png) [@kyle](https://discourse.greatexpectations.io/u/kyle)\
**Post date:** [May 28, 2020, 1:58pm UTC](https://discourse.greatexpectations.io/t/how-to-create-custom-expectations-for-pandas/201/1 "2020-05-28T13:58:27Z")

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This article is for comments to: [https://docs.greatexpectations.io/en/latest/how\_to\_guides/creating\_and\_editing\_expectations/how\_to\_create\_custom\_expectations\_for\_pandas.html](https://docs.greatexpectations.io/en/latest/how_to_guides/creating_and_editing_expectations/how_to_create_custom_expectations_for_pandas.html)

Please comment +1 if this How to is important to you.

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**Author:** ![amiitbhaik07](https://avatars.discourse-cdn.com/v4/letter/a/b5a626/32.png) [@amiitbhaik07](https://discourse.greatexpectations.io/u/amiitbhaik07)\
**Post date:** [May 18, 2021, 10:19am UTC](https://discourse.greatexpectations.io/t/how-to-create-custom-expectations-for-pandas/201/2 "2021-05-18T10:19:15Z")

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Hi, I have successfully created a custom expectation around PandasDataset. While execution, it gets correctly picked up. However, in the HTML result, the details are incomplete. How can I achieve a proper output in HTML format as well? So far, only the custom expectation name and arguments of that method are populated in HTML. I also want some meaningful information to be shown in that report, as to why the expectation failed, what was observed and what is the actual value. Any help is appreciated.

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**Author:** ![Roger](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.greatexpectations.io/roger/32/134_2.png) [@Roger](https://discourse.greatexpectations.io/u/Roger)\
**Post date:** [June 15, 2021, 5:56am UTC](https://discourse.greatexpectations.io/t/how-to-create-custom-expectations-for-pandas/201/3 "2021-06-15T05:56:45Z")

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+1

Could you add some examples of how to implement custom multi-column expectations? I’m just not sure what to return instead of `column.map(lambda x: ...)`.

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**Author:** ![dansasbu](https://avatars.discourse-cdn.com/v4/letter/d/a88e4f/32.png) [@dansasbu](https://discourse.greatexpectations.io/u/dansasbu)\
**Post date:** [September 1, 2021, 7:04pm UTC](https://discourse.greatexpectations.io/t/how-to-create-custom-expectations-for-pandas/201/4 "2021-09-01T19:04:37Z")

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Hi, the link is broken. Where can I find an example of this