How to call genotype bases for all the samples in a vcf using for-loop?

Question

[kirannbishwa01]

I can call genotype bases for one sample at a time separately using pyVCF module as:

        for sample in record.samples:
                call = record.genotype('MA611')
                print(call.gt_bases)

Ouput:

    A/A
    A|G
    G/G
    C|T

But, how can I print the gt_bases for all the samples in a vcf file using for loop. I tried:

        for sample in record.samples:
            for x in record.genotype:
                call = record.genotype(x)
                print(call.gt_bases)

I am getting error:

    for x in record.genotype:
TypeError: 'method' object is not iterable

Thanks !

[WouterDeCoster]

Isn't this an odd loop? You loop over all samples, but never actually use that variable sample in your loop.

for sample in record.samples:
    call = record.genotype('MA611')
    print(call.gt_bases)

Answer 1

[kirannbishwa01]

yes, it is.

call is a method to find several records from a sample. But, sample name needs to be specified. I wanted to do this naturally without having to specify the sample name. But, pyVCF tutorial doesn't really have such example, not it is described elsewhere. So, i resorted to printing the line which is a dictionary then I converted it to string - then split it - then selected the sample name by index -- which finally worked but I think its not a best way to do it. but its ok.

Answer 2

[DG]

Pretty sure you have everything you need there, you're just not using it:

for record in records:
    for sample in record.samples:
        call = record.genotype(sample)
        print(call.gt_bases)

[kirannbishwa01]

@Dan Gaston:

I had a chance to revisit this problem. But, it's still not working.

I tried:

changed other way since there is no method called record

for records in record:  
    for sample in record.samples:
        print(sample) # works
        Call(sample=MA605, CallData(GT=0/0, AD=[4, 0], DP=4, GQ=12, PG=0/0, PL=[0, 12, 163], PW=0/0))

But as soon as I do:

        call = record.genotype(sample)
        print(call.gt_bases)

I get error message:

Traceback (most recent call last):
    File "/home/everestial007/PycharmProjects/stitcher/pHASE-Stitcher-Markov/markov_final_test/for_loop_test_inVcf.py", line 74, in <module>
    call = record.genotype(sample)
    File "/home/everestial007/anaconda3/lib/python3.5/site-packages/vcf/model.py", line 277, in genotype
        return self.samples[self._sample_indexes[name]]
TypeError: unhashable type: '_Call'

The problem is that the output of print(sample) is not a one-word string but a tuple/list.

Any suggestions.

[DG]

the data structure has the attribute sample right there. So instead of call = record.genotype(sample) it looks like it is probably call = record.genotype(sample.sample) or something along those lines.

[kirannbishwa01]

@Dan Gaston: Can you please look into this problem? How to write the variant (allele) information back into a vcf file?