CODEWITHSUNDEEP
r
Shandy Chiu 邱于嫙
Shandy Chiu 邱于嫙

Reputation: 63

R Code in attach()/detach() not work

age <- seq(10, 100, 10)
df <- data.frame(age)
df

this doesnt work

df$agegroup <- vector(mode = "character", length = nrow(df))
attach(df)
agegroup[age >= 10 & age < 20] <- "10To20"
detach(df)
df$agegroup

this works fine

df$agegroup <- vector(mode = "character", length = nrow(df))
df$agegroup[df$age >=10 & df$age < 20] <- "10To20"
df$agegroup

Can somebody explain why is that? thank you!

Upvotes: 0

Views: 725

Answers (1)

user824425
user824425

Reputation:

As mentioned in the documentation of attach:

The database is not actually attached. Rather, a new environment is created on the search path and the elements of a list (including columns of a data frame) or objects in a save file or an environment are copied into the new environment. If you use <<- or assign to assign to an attached database, you only alter the attached copy, not the original object. (Normal assignment will place a modified version in the user's workspace: see the examples.) For this reason attach can lead to confusion.

Upvotes: 4

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