r - how to extract upper/lower bounds on coefficients from quantile regression rq() -

i'd extract coefficients , upper , lower bounds quantile regression using quantreg package. here's example file.

data(engel) attach(engel) taus <- c(.05,.1,.25,.75,.9,.95) f <- rq((foodexp)~(income),tau=taus) sf <- summary(f) sf[1] #[[1]]  #call: rq(formula = (foodexp) ~ (income), tau = taus)  #tau: [1] 0.05  #coefficients: #            coefficients lower bd  upper bd  #(intercept) 124.88004     98.30212 130.51695 #income        0.34336      0.34333   0.38975 

i know can use coefficients() coefficients.

cf <- t(data.frame(coefficients(f)))    # transpose better arrangement cf #              (intercept)    income #tau..0.05   124.88004 0.3433611 #tau..0.10   110.14157 0.4017658 #tau..0.25    95.48354 0.4741032 #tau..0.75    62.39659 0.6440141 #tau..0.90    67.35087 0.6862995 #tau..0.95    64.10396 0.7090685 

but can't figure out how upper/lower bounds appear in summary(). looked @ str(sf), did not see how extract.

ultimately, i'd put taus, coefficients, , upper/lower bounds in dataframe further processing.

i'm assuming want coefficients on non-intercept term. how this

sapply(sf, function(x) c(tau=x$tau, x$coefficients[-1, ])) 

that iterate on different levels of tau , extract intervals coefficients

                  [,1]      [,2]      [,3]      [,4]      [,5]      [,6] tau          0.0500000 0.1000000 0.2500000 0.7500000 0.9000000 0.9500000 coefficients 0.3433611 0.4017658 0.4741032 0.6440141 0.6862995 0.7090685 lower bd     0.3433270 0.3420992 0.4203298 0.5801552 0.6493680 0.6739000 upper bd     0.3897500 0.4507941 0.4943288 0.6904127 0.7422294 0.7344405