df = data.frame(a = c(1, 3, 4, 7),
b = c(12, 98, 87, 20),
c = c(2, 4, 5, 9),
d = c(13, 77, 50, 20),
row.names = c('o', 'p', 's', 't'))
print(df)
df = df[-c(2, 4)]
print(df)
# run:
#
# a b c d
# o 1 12 2 13
# p 3 98 4 77
# s 4 87 5 50
# t 7 20 9 20
# a c
# o 1 2
# p 3 4
# s 4 5
# t 7 9
#