How to extract allel, Genotype from vcf file using python or other language for 23GB files?
Well, I am able to right script to get allel but for large VCF file its difficult ? what should other possible way to get allel, Genotype information?
See [bcftools query][1]. 

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**EDIT:** WIth `bcftools query` you can print any information you like. So in your case e.g.:

    $ bcftools query -f '%CHROM %POS  %REF  %ALT [ %GT]\n' input.vcf

The output looks now like this:

    chr1 10177  ACC  ACCC  0/1
    chr1 10327  T  C  0/0
    chr1 10352  TAC  TAAC  1/1
    chr1 12783  G  A  1/1

fin swimmer
  [1]: http://www.htslib.org/doc/bcftools.html#query