How do I create a For-Loop for these vectors?

Question

This is my current code (I'm a greenhorn!). Although it does the job, but I'm curious to find a more efficient code.

day1_av <- tapply(day1$lots_available, day1$hour, mean) %>% data.frame() 
day2_av <- tapply(day2$lots_available, day2$hour, mean) %>% data.frame() 
day3_av <- tapply(day3$lots_available, day3$hour, mean) %>% data.frame()
day4_av <- tapply(day4$lots_available, day4$hour, mean) %>% data.frame() 
day5_av <- tapply(day5$lots_available, day5$hour, mean) %>% data.frame() 
day6_av <- tapply(day6$lots_available, day6$hour, mean) %>% data.frame() 
day7_av <- tapply(day7$lots_available, day7$hour, mean) %>% data.frame()
day_av <- cbind(day1_av, day2_av, day3_av, day4_av, day5_av, day6_av, day7_av)
day_av

Is there a way to make a for-loop and create a data frame day_av out of this in R? I tried this:

day_av <- data.frame()
for(i in c(1:7)){
day[i]_av <- tapply(day[i]$lots_available, day[i]$hour, mean) %>% data.frame()
day_av <- rbind(day_av, day[i]_av) 

but the square brackets don't seem to send the message across. Appreciate any help, thank you~

Answer 1

You could put all the dataframe in a list and then use tapply over them

output <- do.call(cbind, lapply(mget(paste0('day', 1:7)) function(x)
                         tapply(x$lots_available, x$hour, mean)))