# Setting maximum sequence date

**URL:** <https://nextstrain.discourse.group/t/setting-maximum-sequence-date/215>\
**Category:** Help and Getting Started\
**Created:** [December 3, 2020, 6:39pm UTC](https://nextstrain.discourse.group/t/setting-maximum-sequence-date/215 "2020-12-03T18:39:02Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![garfinjm](https://avatars.discourse-cdn.com/v4/letter/g/3da27b/32.png) [@garfinjm](https://nextstrain.discourse.group/u/garfinjm)\
**Post date:** [December 3, 2020, 6:39pm UTC](https://nextstrain.discourse.group/t/setting-maximum-sequence-date/215/1 "2020-12-03T18:39:02Z")

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Hello,

Is there an way to set the maximum sequence date when using the snakemake script? For example, if I only wanted to select samples collected before 2020-04-01.

Thanks for your help,  
Jake

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**Author:** ![rneher](https://yyz1.discourse-cdn.com/flex031/user_avatar/nextstrain.discourse.group/rneher/32/20_2.png) [@rneher](https://nextstrain.discourse.group/u/rneher)\
**Post date:** [December 3, 2020, 9:06pm UTC](https://nextstrain.discourse.group/t/setting-maximum-sequence-date/215/2 "2020-12-03T21:06:57Z")

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Yes, you can do this! `augur filter` has a flag `--max-date`:

> <https://github.com/nextstrain/augur/blob/master/augur/filter.py#L93>

you should be able to use this as

`augur filter --max-date 2020-04-01`

(and the other arguments for sequences, metadata, and output of course).

best  
richard

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<div class="post-metadata">

**Author:** ![garfinjm](https://avatars.discourse-cdn.com/v4/letter/g/3da27b/32.png) [@garfinjm](https://nextstrain.discourse.group/u/garfinjm)\
**Post date:** [December 4, 2020, 3:09pm UTC](https://nextstrain.discourse.group/t/setting-maximum-sequence-date/215/3 "2020-12-04T15:09:18Z")

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Thanks Richard!

Is there an option to set this paramter in the builds.yaml file when running the snakemake workflow?

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**Author:** ![james](https://yyz1.discourse-cdn.com/flex031/user_avatar/nextstrain.discourse.group/james/32/11_2.png) [@james](https://nextstrain.discourse.group/u/james)\
**Post date:** [December 10, 2020, 2:34am UTC](https://nextstrain.discourse.group/t/setting-maximum-sequence-date/215/4 "2020-12-10T02:34:21Z")

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Not currently (you’d have to modify the actual snakemake file) but you can achieve the same result by adding the `"max_date"` field to each of your subsampling schemes in your build config. E.g. using `my_profiles/example/builds.yaml`

```auto
# Define custom subsampling logic for county-level builds.
subsampling:
  custom-county:
    # Focal samples for location
    focal:
      group_by: "year month"
      max_date: "2020-04-01" # <-- add this to each scheme
      seq_per_group: 300

```

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<div class="post-metadata">

**Author:** ![garfinjm](https://avatars.discourse-cdn.com/v4/letter/g/3da27b/32.png) [@garfinjm](https://nextstrain.discourse.group/u/garfinjm)\
**Post date:** [December 11, 2020, 6:43pm UTC](https://nextstrain.discourse.group/t/setting-maximum-sequence-date/215/5 "2020-12-11T18:43:10Z")

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Ah! That should work for me, thanks for your help!