CODEWITHSUNDEEP
r
Robert
Robert

Reputation: 119

How to assign value from data frame in R?

I have two data frames as follows:

A. Country1 Country2 Country3

B. enter image description here

And I want to assign a specific value based on country and year. The result should be

C. enter image description here

Anyone know how to do automatically? Because table A has over 2,000 rows and 30 years.

Upvotes: 1

Views: 38

Answers (1)

akrun
akrun

Reputation: 887028

An option is to reshape the second data into 'long' format and then do a join

library(dplyr)
library(tidyr)
df2 %>%
    pivot_longer(cols = -Country, names_to = 'Year', values_to = 'Value') %>%
    left_join(df1, .)
#   Country Year  Value
#1 Country1 1990 value1
#2 Country2 1991 value5
#3 Country3 1991 value6

data

df1 <- structure(list(Country = c("Country1", "Country2", "Country3"
), Year = c("1990", "1991", "1991")), row.names = c(NA, -3L),
class = "data.frame")

df2 <- structure(list(Country = c("Country1", "Country2", "Country3"
), `1990` = c("value1", "value2", "value3"), `1991` = c("value4", 
"value5", "value6")), class = "data.frame", row.names = c(NA, 
-3L))

Upvotes: 1

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