mutate() in (d)plyr does not create new column when sourced

Question

I am using the package dplyr with R (same problem applies to plyr, too). When I call source("dply_problem.R") to the following code

library("dplyr")

df <- data.frame("A" = 1:6,
                 "B" = 7:12)
mutate(df, C = A + B)

the column "C" does not get added to df. However, when I call mutate(df, C = A + B) from the shell, the column "C" does get created. Could you give me a hint why this is happening?

Joni

Did you try assigning the output of mutate to "df"? – Mammoth

Answer 1

You haven't assigned the output to anything. Try:

library("dplyr")

df <- data.frame("A" = 1:6,
                 "B" = 7:12)
df <- mutate(df, C = A + B)

df

Mammoth

@Joni if this answer suits your needs you may want to consider marking the checkmark next to it to indicate to future searchers that this answer most correctly suited the question. – Consent

Answer 2

This can also be done using pipe operator. dplyr imports this operator from another package (magrittr)

library(dplyr)
df <- data.frame("A" = 1:6,
                 "B" = 7:12)
df1<- df %>% mutate(C = A + B)

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