data.frame - R getting columns that follow specific pattern -

data.frame - R getting columns that follow specific pattern -

i want select specific columns r dataframe , using below line , works fine:

maindata <- rbind(maindata, dat[c('segment','hwave')])

but want select columns names such q2_1, q2_2 q2_18. how effectively? can type individual column name won't efficient.

the line below gives me error.

maindata <- rbind(maindata, dat[c('segment','hwave','q2_1':'q2_18')])

try:

maindata <- rbind(maindata, dat[c("segment","hwave",paste("q2",1:18,sep="_"))])

r data.frame