# How preprocessing with IterableDataset works?

**URL:** <https://discuss.huggingface.co/t/how-preprocessing-with-iterabledataset-works/12186>\
**Category:** 🤗Datasets\
**Created:** [November 23, 2021, 6:08am UTC](https://discuss.huggingface.co/t/how-preprocessing-with-iterabledataset-works/12186 "2021-11-23T06:08:49Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Modfiededition](https://avatars.discourse-cdn.com/v4/letter/m/ce73a5/32.png) [@Modfiededition](https://discuss.huggingface.co/u/Modfiededition)\
**Post date:** [November 23, 2021, 6:08am UTC](https://discuss.huggingface.co/t/how-preprocessing-with-iterabledataset-works/12186/1 "2021-11-23T06:08:49Z")

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I want to know how functions like map, the filter works with IterableDataset type?

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**Author:** ![mariosasko](https://sea2.discourse-cdn.com/hellohellohello/user_avatar/discuss.huggingface.co/mariosasko/32/31548_2.png) [@mariosasko](https://discuss.huggingface.co/u/mariosasko)\
**Post date:** [December 7, 2021, 1:35pm UTC](https://discuss.huggingface.co/t/how-preprocessing-with-iterabledataset-works/12186/2 "2021-12-07T13:35:58Z")

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Hi,

currently, `IterableDataset` doesn’t support `filter` (you can use a simple check to filter unwanted examples), and for `map` see the docs [here](https://huggingface.co/docs/datasets/master/stream.html?highlight=map#map).