# Extracting entry fields into a separate MatrixTable **URL:** \ **Category:** Hail Query & hailctl\ **Created:** [December 13, 2021, 4:42pm UTC](https://discuss.hail.is/t/extracting-entry-fields-into-a-separate-matrixtable/2405 "2021-12-13T16:42:26Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![CuriousGeneticist](https://avatars.discourse-cdn.com/v4/letter/c/6f9a4e/32.png) [@CuriousGeneticist](https://discuss.hail.is/u/CuriousGeneticist)\ **Post date:** [December 13, 2021, 4:42pm UTC](https://discuss.hail.is/t/extracting-entry-fields-into-a-separate-matrixtable/2405/1 "2021-12-13T16:42:26Z")
Hi all! I have three entry fields in a MatrixTable: _phased\_trio\_dataset.entries().mother\_entry.PBT\_GT_ _phased\_trio\_dataset.entries().father\_entry.PBT\_GT_ _phased\_trio\_dataset.entries().proband\_entry.PBT\_GT_ They are all CallExpressions. Is there a way to save these entries (and the corresponding variants) into a separate MatrixTable? Thank you very much! ---
**Author:** ![danking](https://yyz2.discourse-cdn.com/flex036/user_avatar/discuss.hail.is/danking/32/43_2.png) [@danking](https://discuss.hail.is/u/danking)\ **Post date:** [December 13, 2021, 4:48pm UTC](https://discuss.hail.is/t/extracting-entry-fields-into-a-separate-matrixtable/2405/2 "2021-12-13T16:48:12Z")
Yes! ```auto new_mt = phased_trio_dataset.select_entries( mother_entry = phased_trio_dataset.mother_entry.select('PBT_GT'), father_entry = phased_trio_dataset.father_entry.select('PBT_GT'), proband_entry = phased_trio_dataset.proband_entry.select('PBT_GT') ) ``` * * * Aside: `.entries()` is a very inefficient operation which converts from a 2-d matrix representation to a 1-d table representation. I don’t recommend using it! ---
**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:** [December 13, 2021, 4:50pm UTC](https://discuss.hail.is/t/extracting-entry-fields-into-a-separate-matrixtable/2405/3 "2021-12-13T16:50:30Z")
> [@CuriousGeneticist](#): > > They are all CallExpressions. Is there a way to save these entries (and the corresponding variants) into a separate MatrixTable? Thank you very much! What’s your end goal here? Why is it important that these are in a separate matrixtable? The MatrixTable containing these three fields can probably be used to do what you want. ---
**Author:** ![CuriousGeneticist](https://avatars.discourse-cdn.com/v4/letter/c/6f9a4e/32.png) [@CuriousGeneticist](https://discuss.hail.is/u/CuriousGeneticist)\ **Post date:** [December 13, 2021, 4:57pm UTC](https://discuss.hail.is/t/extracting-entry-fields-into-a-separate-matrixtable/2405/4 "2021-12-13T16:57:26Z")
Thank you so much for your response! I tried something similar myself and got the same result: ![image](https://canada1.discourse-cdn.com/flex036/uploads/hail/original/1X/4e52c075aac38a075059ce91bbb9127ff83c94ef.jpeg) I am not sure of what went wrong. ---
**Author:** ![CuriousGeneticist](https://avatars.discourse-cdn.com/v4/letter/c/6f9a4e/32.png) [@CuriousGeneticist](https://discuss.hail.is/u/CuriousGeneticist)\ **Post date:** [December 13, 2021, 4:58pm UTC](https://discuss.hail.is/t/extracting-entry-fields-into-a-separate-matrixtable/2405/5 "2021-12-13T16:58:23Z")
## This is the what I get with describe(): Page up ``` 'proband_entry': struct { AD: array, DP: int32, GQ: int32, GT: call, MIN_DP: int32, PGT: call, PID: str, PL: array, PS: int32, RGQ: int32, SB: array, PBT_GT: call } 'father_entry': struct { AD: array, DP: int32, GQ: int32, GT: call, MIN_DP: int32, PGT: call, PID: str, PL: array, PS: int32, RGQ: int32, SB: array, PBT_GT: call } 'mother_entry': struct { AD: array, DP: int32, GQ: int32, GT: call, MIN_DP: int32, PGT: call, PID: str, PL: array, PS: int32, RGQ: int32, SB: array, PBT_GT: call } ``` ---
**Author:** ![danking](https://yyz2.discourse-cdn.com/flex036/user_avatar/discuss.hail.is/danking/32/43_2.png) [@danking](https://discuss.hail.is/u/danking)\ **Post date:** [December 13, 2021, 5:08pm UTC](https://discuss.hail.is/t/extracting-entry-fields-into-a-separate-matrixtable/2405/6 "2021-12-13T17:08:41Z")
Ah, my bad, I forgot to repeat the name of the mt when referring to the entry fields: ```auto new_mt = phased_trio_dataset.select_entries( mother_entry = phased_trio_dataset.mother_entry.select('PBT_GT'), father_entry = phased_trio_dataset.father_entry.select('PBT_GT'), proband_entry = phased_trio_dataset.proband_entry.select('PBT_GT') ) ``` I’ve also updated my original post. Aside: This is why I tend to use really short names for my matrix tables like `mt` or `ds`. ---
**Author:** ![CuriousGeneticist](https://avatars.discourse-cdn.com/v4/letter/c/6f9a4e/32.png) [@CuriousGeneticist](https://discuss.hail.is/u/CuriousGeneticist)\ **Post date:** [December 14, 2021, 6:33pm UTC](https://discuss.hail.is/t/extracting-entry-fields-into-a-separate-matrixtable/2405/7 "2021-12-14T18:33:15Z")
Hi @danking, thank you so much for that! Apologies for a quick follow-up question, but I am trying to retain only the heterozygous phased SNPs in the mt with this: _new\_mt\_het = new\_mt.filter\_entries(hl.agg.any(new\_mt.entries().proband\_entry.PBT\_GT.is\_het()))_ However, that gave me the error: ![image](https://canada1.discourse-cdn.com/flex036/uploads/hail/original/1X/ad0e2668858e503b21bb15ca30113f49662eef9d.jpeg) May I know what went wrong? It worked for me before. ---
**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:** [December 14, 2021, 6:42pm UTC](https://discuss.hail.is/t/extracting-entry-fields-into-a-separate-matrixtable/2405/8 "2021-12-14T18:42:34Z")
```auto new_mt_het = new_mt.filter_entries(hl.agg.any(new_mt.proband_entry.PBT_GT.is_het())) ``` I took out the `.entries()` after `new_mt`. That was the problem. Calling `entries` is saying “make me a new table based on this MatrixTable that has a row for each entry”. You were getting the `proband_entry` field of that new table, instead of the `MatrixTable`, so it told you were using a mix of expressions from two different data sources. ---
**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:** [December 14, 2021, 6:44pm UTC](https://discuss.hail.is/t/extracting-entry-fields-into-a-separate-matrixtable/2405/9 "2021-12-14T18:44:22Z")
@CuriousGeneticist if you haven’t, you should take a look at the visual cheat sheets, which can provide visualizations of what various table / matrixtable operations are doing: [https://hail.is/docs/0.2/cheatsheets.html](https://hail.is/docs/0.2/cheatsheets.html)