Binding multiple columns with different names into one column with the same column name

In the dataframe below, I want to stack the three columns with different names (s_psy01, l_psy01, r_psy01) and name it as psy01. The same goes for the other two sets of columns. How can I do this using preferably dplyr or through alternative methods.

nr=c(1:6)
s_psy01=c(NA,NA,NA,NA,4,5)
l_psy01=c(NA,NA,2,3,NA,NA)
r_psy01=c(2,5,NA,NA,NA,NA)
s_psy02=c(NA,NA,NA,NA,2,3)
l_psy02=c(NA,NA,5,2,NA,NA)
r_psy02=c(3,5,NA,NA,NA,NA)
s_psy03=c(NA,NA,NA,NA,2,4)
l_psy03=c(NA,NA,2,5,NA,NA)
r_psy03=c(1,3,NA,NA,NA,NA)
df <- data.frame(nr,s_psy01, l_psy01, r_psy01,
                    s_psy02, l_psy02, r_psy02,
                    s_psy03, l_psy03, r_psy03)

>Solution :

One approach with pivot_longer – capture the non-digits (\\D+) and the digits (\\d+) till the end ($) of the string from the _ as a single group in names_pattern for the corresponding .value specified in names_to to concatenate the column values that match the substring suffix into a single column in the long format

library(tidyr)
pivot_longer(df, 
  cols =-nr, names_to = c("prefix", ".value"), 
   names_pattern = "(.*)_(\\D+\\d+)$", values_drop_na = TRUE)

-output

# A tibble: 6 × 5
     nr prefix psy01 psy02 psy03
  <int> <chr>  <dbl> <dbl> <dbl>
1     1 r          2     3     1
2     2 r          5     5     3
3     3 l          2     5     2
4     4 l          3     2     5
5     5 s          4     2     2
6     6 s          5     3     4