How to use variables while calling pybedtools

Question

I am trying to use bedtools and fetch sequences from a whole genome fasta file inside the script I get region coordinates as variables. For example:

chr_ = "chr1"
start = 3000
end = 3402

I am not sure how to wrap my function, because the example provided by BedTool.sequence only uses coordinates in a string form.

Can you please help me to have something like this?

a = pybedtools.BedTool(chr_, start, end, from_variables=True)

Answer 1

You have to take your variables and make them into a single string variable.

for example:

chr_ = "chr1"
start = 3000
end = 3402
as_str = ' '.join([chr_, str(start), str(end)])
# or 
as_str2 = "{} {} {}".format(chr_, start, end)

Once you have the string built you can use the example in the bedTool docs.

a = BedTool(as_str, from_string=True)