Merge two columns to a value range column in R

Question

I have a data.frame that looks like this.

dat1=data.frame(begin=c(1,100,50,1000), end=c(100,200,400,2000), functions=c("A","B","C","D"))

begin   end    functions
 1      100       A
100     200       B
50      400       C
1000    2000      D

I would like to convert this data frame to value range data.frame to be able to map another single data point data.frame.

range         functions
1:100           A
100:200         B
50:400          C
1000:2000       D

This is my single point data.frame that I would like to map in the range.

dat2=data.frame(position=c(20,80,200, 1200, 1500))

position    
   20         
   80        
   200       
   1200  
   1500

I want to generate a data.frame that looks like this. Not exactly like but at least to incorporate the Infos of the functions of each position.

position    function1 fucntion2
   20         A
   80         A          C
   200        B          C
   1200       D
   1500       D

Thank you for your time. Any help and direction are appreciated

Answer 1

Does this get you the information you need? You can then pivot_wider() or tweak it to however you want it formatted.

library(dplyr)
library(tidyr)

dat2 %>% 
  crossing(dat1) %>% 
  filter(position >= begin & position <= end)

# A tibble: 7 x 4
  position begin   end functions
     <dbl> <dbl> <dbl> <chr>    
1       20     1   100 A        
2       80     1   100 A        
3       80    50   400 C        
4      200    50   400 C        
5      200   100   200 B        
6     1200  1000  2000 D        
7     1500  1000  2000 D 

Answer 2

Does this work:

> library(purrr)
> library(dplyr)
> dat1 %>% mutate(range = map2(begin, end, `:`)) %>% unnest(range) %>% right_join(dat2, by = c('range' = 'position'), keep = T) %>% select(-range)
# A tibble: 7 x 4
  begin   end functions position
  <dbl> <dbl> <chr>        <dbl>
1     1   100 A               20
2     1   100 A               80
3   100   200 B              200
4    50   400 C               80
5    50   400 C              200
6  1000  2000 D             1200
7  1000  2000 D             1500
>