CODEWITHSUNDEEP
rseq
Christina
Christina

Reputation: 85

How can I use the seq function on two columns in a dataframe?

Suppose I have: 

x <- c(1, 2, 3, 4, 5)
y <- c(2, 3, 6, 8, 10)
my.list <- list(start = x, end = y) %>% as.data.frame()

I need to define a new variable that contains seq(start,end) or start:end stored in that variable, I want the sequence of numbers across the rows, for example, 1 2 for the first row and 3 4 5 6 for the third row.

Many thanks

Upvotes: 3

Views: 845

Answers (1)

akrun
akrun

Reputation: 887951

We can use map2 to get the sequence of corresponding values of 'start', 'end' to create a list of vectors

library(dplyr)
library(purrr)
my.list %>% 
   mutate(new = map2(start, end, `:`))
#  start end               new
#1     1   2              1, 2
#2     2   3              2, 3
#3     3   6        3, 4, 5, 6
#4     4   8     4, 5, 6, 7, 8
#5     5  10 5, 6, 7, 8, 9, 10

Another option is rowwise

my.list %>% 
    rowwise %>% 
    mutate(new = list(start:end))
# A tibble: 5 x 3
# Rowwise: 
#  start   end new      
#  <dbl> <dbl> <list>   
#1     1     2 <int [2]>
#2     2     3 <int [2]>
#3     3     6 <int [4]>
#4     4     8 <int [5]>
#5     5    10 <int [6]>

Or with data.table as @markus mentioned in comments

library(data.table)
setDT(my.list)[, V3 := Map(`:`, start, end)]

Or with Map from base R

Map(`:`, my.list$start, my.list$end)

Upvotes: 5

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