how to use the feature-table group method

Hi! I have been trying to use the qiime feature-table group command to group my data but cannot seem to get it to work how I need to. I am trying to group the data by the separate sample types within the sample_type column of my metadata. The goal is to end up with only one featureID per sample_type. I originally have 812 sampleIDs but want to end up with five or six that represent the culmination of all of the samples of each type. Here is the code I have been trying to use,

qiime feature-table group
--i-table table_noW.qza
--m-metadata-file Mapper.tsv
--m-metadata-column sample_type
--p-mode median-ceiling
--p-axis sample
--o-grouped-table grouped-table_noW.qza

When I do this though I end up with a table to shows all 812 of the sampleIDs with a single culumn next to them that shows what the sample type is. How can i get this code to group the samlpe together into one representation of each sample-type?

Hello @PinoyNaHilaw,

The following is what I would have expected to have happened given you command, correct me where I'm wrong.

This is what your metadata file looks like:

sample-id sample-type
1 A
2 A
3 A
4 B
5 B
... ...
812 C

This is what your pre-grouping feature table looks like:

sample-id-1 sample-id-2 sample-id-3 sample-id-4 ...
feature-1 5 4 0 8 ...
feature-2 7 19 82 40 ...
feature-3 0 4 3 17 ...
... ... ... ... ... ...

This is what your post-grouping feature table looks like:

sample-type-A sample-type-B sample-type-C
feature-1 8 12 0
feature-2 0 1 31
feature-3 4 44 6
... ... ... ...

You grouped along the sample (top) axis, getting the median-ceiling of each set of samples that belongs to a sample-type group.

When I do this though I end up with a table to shows all 812 of the sampleIDs with a single culumn next to them that shows what the sample type is.

Are you sure you're not confusing features and samples? Features are listed along the vertical axis in a feature table. Do you really have 812 samples? It seems more likely that you have 812 features.

The goal is to end up with only one featureID per sample_type.

This doesn't make sense to me. What is this feature supposed to represent for each sample?

Thanks for replying! I might not have been as clear as I thought when asking this question. I most definitely have 812 features in the vertical axis as you pointed out, not samples. I guess a more accurate way to describe my goal is that we want to combine together all the features that have the same sample_type which would leave us with five features, one for each sample_type.

Hello @PinoyNaHilaw,

Okay, it sounds like you want to average feature abundances together according to what sample_type they belong to. To do this you need the necessary information in your metadata and you need to group along the feature axis, not the sample axis: --p-axis feature.

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when I use --p-axis feature instead of --p-axis sample I get a very long string of red text that looks to me like a list of the feature IDs and an error message that says "Debug info has been saved to /tmp/qiime2-q2cli-err-bhehoafj.log". Is there maybe something wrong with my metadata file? or maybe something wrong with my --table artifact?

Hello @PinoyNaHilaw,

Can you share the entire error output?

of course! here is the end of it. the whole message is too long so I am only inlcuding the very end of it.

. . . , 'ffe9786a0b9627d995e97b7a11e444a2', 'fff29f87da824918c97b0f8ecfaa82e4', 'fff7db3a5e859a932293e352e1e619a7'

Debug info has been saved to /tmp/qiime2-q2cli-err-osq58za9.log

and when i call head on the tmp/qiime2.log message I get

Traceback (most recent call last):
File "/home/miniconda3/envs/qiime2/lib/python3.6/site-packages/q2cli/commands.py", line 329, in call
results = action(**arguments)
File "", line 2, in group
File "/home/miniconda3/envs/qiime2/lib/python3.6/site-packages/qiime2/sdk/action.py", line 245, in bound_callable
output_types, provenance)
File "/home/miniconda3/envs/qiime2/lib/python3.6/site-packages/qiime2/sdk/action.py", line 390, in callable_executor
output_views = self._callable(**view_args)
File "/home/miniconda3/envs/qiime2/lib/python3.6/site-packages/q2_feature_table/_group.py", line 51, in group
axis)

Hello @PinoyNaHilaw,

If the output is too long to paste here, you can upload a log file instead with everything in it.

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