Coordinates to Genome R Studio Script? I have a very, very long list of genome coordinates of areas. I need to gather a sequence in order to compare it to another database of sequences that I have. How do I produce the genome sequences from these coordinates in R?

I am very new to this and need a detailed answer.
This doesn't use R, but a simple and quite convenient method is to use bedtools getfasta with your fasta file. You'll need to make a BED file out of the RepeatMasker output:

awk 'BEGIN{OFS="\t"}{name=sprintf("%s_%s", $10, $11); strand="+"; if($9 == "C"){strand="-"}; print $5,$6-1,$7,name,".", strand}' repeatmasker.output &gt; rmsk.bed


Then, given that and your genome.fa fasta:

bedtools getfasta -name -s -fi genome.fa -bed rmsk.bed -fo output.fa


This will produce a multiline fasta file names like AluSx_SINE/Alu (due to the -name option) where the sequences are reverse complemented if appropriate.

You can install bedtools either via conda (conda install -c bioconda bedtools) or github.