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rdataframedplyrdivision

How to divide only a certain factor in a column in R data frame?

This is the sample dataset:

library(data.table)
df = data.table(x = c(1000,2000,10,2), y = c('A','A','B','B'))

I only want to divide df$y == "A" by 1000. The final dataset should appear as:

df = data.table(x = c(1,2,10,2), y = c('A','A','B','B'))
Solution

  • You need to create a conditional statement.

    In base R:

    df$x <- ifelse(df$y == "A", df$x/1000, df$x)

    In dplyr:

    library(dplyr)
df <- df |>
    mutate(x = if_else(y == "A", x/1000, x))