CODEWITHSUNDEEP
rsubset
user974887
user974887

Reputation: 2489

R - How to add data to a new column by subset conditions?

I'm trying to add values to a new column based on values in another column. Using the iris data as an example my basic logic is "If iris$Sepal.Length > 5, then iris$size == 'TRUE'".

> head(iris, 2)
  Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1          5.1         3.5          1.4         0.2  setosa
2          4.9         3.0          1.4         0.2  setosa

Using the iris data as an example my basic logic is "If iris$Sepal.Length > 5, then iris$size == 'TRUE'" to produce:

  Sepal.Length Sepal.Width Petal.Length Petal.Width Species size
1          5.1         3.5          1.4         0.2  setosa   TRUE
2          4.9         3.0          1.4         0.2  setosa   NA

I can subset the data, but can't get the syntax to pass a value back. Something like this?

subset(iris, iris$Sepal.Length >= 5) %>% iris$size == 'TRUE'

Upvotes: 0

Views: 1342

Answers (4)

forestfanjoe
forestfanjoe

Reputation: 412

Either:

iris$size <- iris$Sepal.Length >= 5

Or if you want to go down the tidyverse route

iris %>% mutate(size = Sepal.Length >= 5)

Upvotes: 2

akrun
akrun

Reputation: 887158

Using dplyr. The output of a logical expression is TRUE/FALSE. It is better not to create a character output

library(dplyr)
iris %>%
    mutate(size = Sepal.Length >=5)

Upvotes: 2

SmitM
SmitM

Reputation: 1376

You could do something like this using the ifelse statement

iris$Size <- ifelse(iris$Sepal.Length >= 5, "TRUE", "FALSE")

Upvotes: 2

iod
iod

Reputation: 7592

iris$size[iris$Sepal.Length>=5] <- TRUE

This basically reads as "put TRUE into iris$size for those rows where iris$Sepal.Length is equal or greater than 5".

Upvotes: 2

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