Count Number of List Elements in R
In this article, we are going to find the length of a list in R and count the elements in a list and elements in a nested list in R Programming Language. So we are going to use length() and lengths() to find the length of the list in R.
Steps –
- Create a list with vectors/list/range operator
- Find the count of elements using the length and lengths function.
Syntax: list(value1,value2,…,value)
values can be range operator or vector.
Using length() function
The length function is used to count the elements in the list.
Syntax: length(listname)
return value: integer
Let’s create a list and find the length of list
R
# Create a sample list a1 <- list ( "Beginner" , "For" , "Beginner" ) # Print the length print ( length (a1)) |
Output:
[1] 3
Now let us create an empty list and find the length of list
R
# create empty list empty_list<- list () # print length of the empty list print ( length (empty_list)) |
Output:
[1] 0
Let’s create a list using the range, vector, and list and find the length of list
R
# Create a list using range, vector, and list vec <- 1:5 # Creates a sequence from 3 to 9 with a step of 2 my_range <- seq (3, 9, by = 2) # Combine the vector and range into a single list my_list <- list (numbers = vec, sequence = my_range, fruits = c ( "apple" , "banana" , "orange" )) # Print the list print (my_list) # Print the length print ( length (my_list)) |
Output:
$numbers
[1] 1 2 3 4 5
$sequence
[1] 3 5 7 9
$fruits
[1] "apple" "banana" "orange"
[1] 3
For finding the length of each data in a list (nested list) we will use lengths() function
Syntax: lengths(list_name)
R
# range from 10 to 50 values = 10:50 # vector elements of character type names = c ( "sravan" , "bobby" , "ojaswi" , "gnanu" ) # data1 with list of elements data1 = list (1, 2, 3, 4, 5) # give input to the data which is a list data = list (a1 = values, a2 = names, a3 = data1) # display print (data) # count elements in each nested using lengths function print ( lengths (data)) |
Output:
$a1
[1] 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37
[29] 38 39 40 41 42 43 44 45 46 47 48 49 50
$a2
[1] "sravan" "bobby" "ojaswi" "gnanu"
$a3
$a3[[1]]
[1] 1
$a3[[2]]
[1] 2
$a3[[3]]
[1] 3
$a3[[4]]
[1] 4
$a3[[5]]
[1] 5
a1 a2 a3
41 4 5
R program count elements in a nested list
R
# data1 with list of elements data1 = list (1, 2, 3, 4, 5) # data2 with list of elements data2 = list ( "a" , 'b' , 'c' ) # give input to the data which is a list data = list (a1 = data1, a2 = data2) # display print (data) # count elements in each nested using length function print ( length (data)) print ( "-----" ) # count elements in each nested using lengths function print ( lengths (data)) |
Output:
$a1
$a1[[1]]
[1] 1
$a1[[2]]
[1] 2
$a1[[3]]
[1] 3
$a1[[4]]
[1] 4
$a1[[5]]
[1] 5
$a2
$a2[[1]]
[1] "a"
$a2[[2]]
[1] "b"
$a2[[3]]
[1] "c"
[1] 2
[1] "-----"
a1 a2
5 3
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