[R] how to GREP out a string like this......THANKS.

Dear ALl, I hope you could help me out on this simple problem. I have many thousand lines like this: NM_019397 // Egfl6 // EGF-like-domain, multiple 6 // X F5|X 71.5 cM // 54156 I want to extract the string inside the first // //, in this case is Egf16. How do I apply grep function? Thanks.

[R] a newbie seeking for a simple problem

Dear Experienced R users, I have a looks-like simple but complicated problem urgently needed to be solved. Below is the detail: I have two dataframes, df1, df2. df1 contains two column and many thousands rows: column 1 is a gene_name, column 2 is value. df2 contains only one column which is