Concatenating two text columns in dplyr

You can use the unite function from tidyr

require(tidyverse)

df %>% 
  unite(round_experiment, c("round", "experiment"))

  round_experiment   results
1             A_V1  8.797624
2             A_V2  9.721078
3             A_V3 10.519000
4             B_V1  9.714066
5             B_V2  9.952211
6             B_V3  9.642900

This should do the trick if you are looking for a new variable

library(tidyverse)

round <- c(rep("A", 3), rep("B", 3))
experiment <- rep(c("V1", "V2", "V3"), 2)
results <- rnorm(mean = 10, n = 6)

df <- data.frame(round, experiment, results)
df

df <- df %>% mutate(
  name = paste(round, experiment, sep = "_")
)