CODEWITHSUNDEEP
r
gojomoso
gojomoso

Reputation: 163

R Evaluate if a Value Exists in Another Table

df1:

a = c(2, 3, 5, 8, 10, 12) 
b = c("aa", "bb", "cc", "aa", "bb","aa") 
c = c(TRUE, FALSE, TRUE, FALSE, TRUE, FALSE) 
df1 = data.frame(a, b, c)

df2:

df2 = c("aa", "bb")

I want to evaluate df1$b to see if the value is in df2$d. If it is, then keep the value. If it's not then input "Rare"

Output: df1

a  b    c
2  aa   true
3  bb   false
5  rare true
8  aa   false
10 bb   true
12 aa   false

Upvotes: 0

Views: 1220

Answers (2)

Serhii
Serhii

Reputation: 422

A data.table way would look the following:

# Load library
library(data.table)

# Convert created tables to data.table object
setDT(df1)

# Add 'rare' 
df1[!b %in% df2, b := "rare"]

If df2 is a table (not a vector like it is in the original post and the code chunk above), then you should reference the appropriate column. For example, df2$b

The outcome:

> df1
    a    b     c
1:  2   aa  TRUE
2:  3   bb FALSE
3:  5 rare  TRUE
4:  8   aa FALSE
5: 10   bb  TRUE
6: 12   aa FALSE

Upvotes: 1

Duck
Duck

Reputation: 39595

This can be done in base R:

#Data
a = c(2, 3, 5, 8, 10, 12) 
b = c("aa", "bb", "cc", "aa", "bb","aa") 
c = c(TRUE, FALSE, TRUE, FALSE, TRUE, FALSE) 
df1 = data.frame(a, b, c,stringsAsFactors = F)
df2 <- data.frame(d=c("aa", "bb"),stringsAsFactors = F)
#Compute
df1$b <- ifelse(df1$b %in% df2$d,df1$b,'rare')

Output:

   a    b     c
1  2   aa  TRUE
2  3   bb FALSE
3  5 rare  TRUE
4  8   aa FALSE
5 10   bb  TRUE
6 12   aa FALSE

Upvotes: 1

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