Count Number of List Elements in R

In this article, we are going to 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 elements count in a list.

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.

Let’s create a list using the range, vector, and list.

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(values, names, data1)

# display
print(data)

Output:

Example 1: Using length() function.

Length function is used to count the elements in the list

Syntax: length(listname)

return value: integer

Below is the implementation:

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(values, names, data1)

# display
print(data)

# count elements using length function
print(length(data))

Output:

Example 2: For finding the length of each data in a list (nested list) we will use lengths() function

Syntax: lengths(list_name)

Below is the implementation:

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:

Example 3: 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: