sorry merged file is like so ID substanceBXH GENE_SYMBOL
A_55_P2280868 MMT00026679 0610005C13Rik
A_52_P7183 MMT00001605 0610007L01Rik
A_52_P194464 MMT00082066 0610007P08Rik
dim(merg) [1] 11012 3
I have another file contains expression profiles
substanceBXH F2_2 F2_3
A_30_P01033363 4.920370 5.128868
A_55_P1965358 6.673461 6.559542
A_66_P122433 3.925836 3.671287
DarkCorner 3.447131 2.805281
dim(mycounts) [1] 2256 13
how I can extract 2256 MMT00026679 matched and the correspond expression profile from mycounts file?