Add new column to dataframe depending on upper limit

Question

I have a dataset in which I want regarding to one of the num_values add new value from the other dataframe.

Here's an example, create some df1

First.Name <- c("John", "Edgar", "Walt", "Jane")
Second.Name <- c("Doe", "Poe", "Whitman", "Austen")
num_value <- runif(4,0,1.2)
df1 <- data.frame(First.Name, Second.Name, num_value)

which has this output

 First.Name Second.Name  num_value
1       John         Doe 0.08137931
2      Edgar         Poe 0.30245512
3       Walt     Whitman 0.62542554
4       Jane      Austen 0.40573224

df2 is defined as

upper_boundary <- seq(0,1.6,0.2)
class_value <- c(1:9)
df2 <- data.frame(upper_boundary, class_value)

and has it's output as

  upper_boundary class_value
1            0.0           1
2            0.2           2
3            0.4           3
4            0.6           4
5            0.8           5
6            1.0           6
7            1.2           7
8            1.4           8
9            1.6           9

What I'd like to do is to add at the end of the first data frame class value from df2. Output should be something like

       First.Name Second.Name  num_value     class_value  
    1       John         Doe 0.08137931         2
    2      Edgar         Poe 0.30245512         3
    3       Walt     Whitman 0.62542554         5
    4       Jane      Austen 0.40573224         4

Thanks in advance

Possible duplicate of https://stackoverflow.com/q/40380112/680068 — zx8754, Sep 23 '20 at 14:37

score 0 · Answer 1 · answered Sep 23 '20 at 14:37

0

cut and findInterval will work here. I'll use the second,

df1$class_value <- df2$class_value[ findInterval(df1$num_value, df2$upper_boundary) ]
df1
#   First.Name Second.Name num_value class_value
# 1       John         Doe 0.1908379           1
# 2      Edgar         Poe 0.5045381           3
# 3       Walt     Whitman 0.1925997           1
# 4       Jane      Austen 0.2674465           2

answered Sep 23 '20 at 14:37

r2evans

141,215
6
77
149

Most likely a dupe, please search before answering. – zx8754 Sep 23 '20 at 14:39
1

@zx8754, answering a dupe is not always evil. https://meta.stackexchange.com/questions/50358/what-is-with-people-who-answer-questions-that-are-known-to-be-dupes – r2evans Sep 23 '20 at 14:42

score 0 · Answer 2 · answered Sep 23 '20 at 14:38

0

Try cut like below

df1$class_value <- df2$class_value[as.integer(cut(df1$num_value,df2$upper_boundary))+1]

answered Sep 23 '20 at 14:38

ThomasIsCoding

96,636
9
24
81

Most likely a dupe, please search before answering. – zx8754 Sep 23 '20 at 14:39
Nice `as.integer`! +1 – jay.sf Sep 23 '20 at 14:41
ThomasIsCoding, I've wondered many times, do you know of any differences between `findInterval` and `as.integer(cut(...))`? I often do this (as.int(cut)), but am growing into findInt. – r2evans Sep 23 '20 at 14:44
@r2evans they are very similar but different in the indexing of the interval. Mayb you can see that when using the same breaks in two commands – ThomasIsCoding Sep 23 '20 at 15:08

Add new column to dataframe depending on upper limit

2 Answers2