# Filter samples from MatrixTable **URL:** \ **Category:** Hail Query & hailctl\ **Created:** [September 10, 2020, 8:53pm UTC](https://discuss.hail.is/t/filter-samples-from-matrixtable/1645 "2020-09-10T20:53:56Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![nonchev](https://avatars.discourse-cdn.com/v4/letter/n/54ee81/32.png) [@nonchev](https://discuss.hail.is/u/nonchev)\ **Post date:** [September 10, 2020, 8:53pm UTC](https://discuss.hail.is/t/filter-samples-from-matrixtable/1645/1 "2020-09-10T20:53:57Z")
Hello, i want to filter from MatrixTable only individuals(samples) of interest I found in previous post: > mt.filter\_rows(mt.s == ‘NA00001’) which works for single sample, but how can I filter it if I have a list of samples such as: > samples = [‘NA00001’, ‘NA00002’] ---
**Author:** ![johnc1231](https://yyz2.discourse-cdn.com/flex036/user_avatar/discuss.hail.is/johnc1231/32/286_2.png) [@johnc1231](https://discuss.hail.is/u/johnc1231)\ **Post date:** [September 10, 2020, 8:59pm UTC](https://discuss.hail.is/t/filter-samples-from-matrixtable/1645/2 "2020-09-10T20:59:23Z")
`mt.filter_cols(hl.array(samples).contains(mt.s))` ---
**Author:** ![Shiri.Margalit](https://avatars.discourse-cdn.com/v4/letter/s/a3d4f5/32.png) [@Shiri.Margalit](https://discuss.hail.is/u/Shiri.Margalit)\ **Post date:** [April 8, 2021, 12:33pm UTC](https://discuss.hail.is/t/filter-samples-from-matrixtable/1645/3 "2021-04-08T12:33:23Z")
Hi, I’m doing exactly this solution and I’m getting this error: TypeError: array: parameter ‘collection’: expected expression of type set or array or dict\<(‘any’, ‘any’)\>, found This is my code: samples = table[‘target panel prefix’] mt = mt.filter\_cols(hl.array(samples).contains(mt.s)) What can be the reason? Thanks! Shiri ---
**Author:** ![tpoterba](https://yyz2.discourse-cdn.com/flex036/user_avatar/discuss.hail.is/tpoterba/32/61_2.png) [@tpoterba](https://discuss.hail.is/u/tpoterba)\ **Post date:** [April 8, 2021, 1:14pm UTC](https://discuss.hail.is/t/filter-samples-from-matrixtable/1645/4 "2021-04-08T13:14:53Z")
`samples` here isn’t a python list, it’s a table field. If you do: ```auto samples = table['target panel prefix'].collect() ``` This should work, I think ---
**Author:** ![Shiri.Margalit](https://avatars.discourse-cdn.com/v4/letter/s/a3d4f5/32.png) [@Shiri.Margalit](https://discuss.hail.is/u/Shiri.Margalit)\ **Post date:** [April 8, 2021, 1:19pm UTC](https://discuss.hail.is/t/filter-samples-from-matrixtable/1645/5 "2021-04-08T13:19:29Z")
> [@tpoterba](#): > > table field Thank you so much, it worked! ---
**Author:** ![shuang](https://avatars.discourse-cdn.com/v4/letter/s/f08c70/32.png) [@shuang](https://discuss.hail.is/u/shuang)\ **Post date:** [October 21, 2021, 1:59pm UTC](https://discuss.hail.is/t/filter-samples-from-matrixtable/1645/6 "2021-10-21T13:59:58Z")
Hi, If I have a txt file which listed all samples ID without header. Looks like: ```auto 11111111 2222222 3333333 AAAAAA ``` Now I want to filter out these samples from my MT file. What should I do? with Hail v0.1 I do: ```auto to_remove = hc.import_table('outliers.txt', no_header=True).key_by('f0') vds_filtered = vds.filter_samples_table(to_remove, keep=False) ``` I am new to v0.2. According the above answer, I think it might should be: ```auto to_remove = hl.import_table('outliers.txt', no_header=True).key_by('f0') samples_to_remove = to_remove.collect() filtered_mt = mt.filter_cols(hl.array(samples_to_remove).contains(mt.s), keep=False) ``` But I am not sure about it and I do not understand what ‘.contains(mt.s)’ do, any help? Thanks a lot! ---
**Author:** ![shuang](https://avatars.discourse-cdn.com/v4/letter/s/f08c70/32.png) [@shuang](https://discuss.hail.is/u/shuang)\ **Post date:** [October 22, 2021, 3:19pm UTC](https://discuss.hail.is/t/filter-samples-from-matrixtable/1645/7 "2021-10-22T15:19:41Z")
I make it work by: ```auto sample_table = hl.import_table('outlier.txt', no_header=True).key_by('f0') filt_mt = mt.filter_cols(hl.is_defined(sample_table[mt.col_key]), keep=False) ``` ---
**Author:** ![tpoterba](https://yyz2.discourse-cdn.com/flex036/user_avatar/discuss.hail.is/tpoterba/32/61_2.png) [@tpoterba](https://discuss.hail.is/u/tpoterba)\ **Post date:** [October 22, 2021, 3:21pm UTC](https://discuss.hail.is/t/filter-samples-from-matrixtable/1645/8 "2021-10-22T15:21:17Z")
that solution is exactly what we would have suggested! There’s also a set of `anti_join` methods which translates to “remove keys appearing in this other table” that can make this a little more terse: ```python sample_table = hl.import_table('outlier.txt', no_header=True).key_by('f0') filt_mt = mt.anti_join_cols(sample_table) ``` ---
**Author:** ![shuang](https://avatars.discourse-cdn.com/v4/letter/s/f08c70/32.png) [@shuang](https://discuss.hail.is/u/shuang)\ **Post date:** [October 22, 2021, 3:31pm UTC](https://discuss.hail.is/t/filter-samples-from-matrixtable/1645/9 "2021-10-22T15:31:08Z")
Thanks Tim and good to know this “.anti\_join\_cols” method!