change value at specific location in a tibble

Question

I have a df

df = data.frame(col1=1:4, col2 = 5:8, col3 = 9:12)

I want to change the value in row2, col2 to 44

In base R, I use df["2","col2"] = 44, how do I do this in tidyverse?

df = data.frame(col1=1:4, col2 = 5:8, col3 = 9:12)
df
df["2","col2"]=44
df

Answer 1

A possible solution:

library(dplyr)

df %>% 
  mutate(col2 = ifelse(row_number() == 2, 44, col2))

#>   col1 col2 col3
#> 1    1    5    9
#> 2    2   44   10
#> 3    3    7   11
#> 4    4    8   12