Hello,
BC106081_abc_128240811_128241377 7.96301
BC106081_abc_128240811_128241377 39.322
BC106081_cde_128240811_128241377 1.98628
BC106081_def_128240811_128241377 -2.44492
BC106081_abc_128240811_128241377 69.5504
FLJ00075_xyz_14406_16765 -0.173417
FLJ00075_abc_14406_16765 -0.173417
FLJ00075_def_14406_16765 0.46909
FLJ00075_abc_14406_16765 0.46909
Now based on 1st column 1st value before the 1st underscore (BC106081,FLJ00075) extract the max value from column 2
o/p
BC106081 69.5504
FLJ00075 0.46909
Thanks,