r - Filter table rows that contain at least X observations with value larger (or equal) than Y -

i trying filter table rows contain @ least 3 observation values larger or equal 0.7. here example of in r:

   sa  sb  sc  sd  se  sf g1 0.1 0.2 0.8 1.2 0.5 0.0 g2 0.7 0.3 0.9 0.8 0.5 1.0 g3 0.2 0.3 0.8 0.9 0.5 0.0 g4 0.5 0.4 0.9 0.7 0.5 1.0 g5 0.2 0.2 0.8 0.9 0.5 0.0 

filtering result in:

   sa  sb  sc  sd  se  sf g2 0.7 0.3 0.9 0.8 0.5 1.0 g4 0.5 0.4 0.9 0.7 0.5 1.0 

can me out on problem?

if x data,

   > x[rowsums(x >= 0.7) >= 3,]             sa  sb  sc  sd  se sf         g2 0.7 0.3 0.9 0.8 0.5  1         g4 0.5 0.4 0.9 0.7 0.5  1