How to add Key Value Pair to List in R ?
A key-value pair can be explained as a set of two linked data items where a key uniquely identifies a value or a set of values in the data. Since a list can hold multiple data-types data, we can have a key-value pair stored in the list
Method 1:
We can assign variables to each key and value. Store each key-value pair after building the list using square brackets.
R
rm (list = ls ()) # create key value variables key1 <- "Age" value1 <- 21 key2 <- "Name" value2 <- "Pulkit" # create the list mylist <- list () # Build up key value pairs mylist[[ key1 ]] <- value1 mylist[[ key2 ]] <- value2 # Access value using the key print (mylist$Age) print (mylist$Name) |
Output:
21 Pulkit
Method 2:
Another way of doing this without using any additional variables is to specify the key and the value in the list() function while creating the list.
Example
R
rm (list = ls ()) # Creating the list mylist<- list ( "Name" = "Pulkit" , "Age" =21, "Gender" = "Male" ) # Access value using the key print (mylist$Age) print (mylist$Gender) |
Output:
21 Male
Method 3: Using setNames()
Another approach we can take to add a key-value pair in the list is to setNames() function and inside it, we use as.list(). Basically what we will have here is a syntax like given below, which will create a list and assign all the keys with their respective values.
Syntax:
variable<-setNames(as.list(values), keys)
Example:
R
rm (list = ls ()) # initialize keys and respected values students <- c ( "Pulkit" , "Ritika" , "Parth" , "Vishesh" , "Dharvik" , "krishav" , "Reshav" ) marks <- c (75, 92, 97, 80, 85, 87, 52) # make the list results <- setNames ( as.list (marks), students) # Access value using the key print (results$Pulkit) |
Output:
75
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