R - Create empty vector and append values

In this article, we will discuss how to create an empty vector and add elements into a vector in R Programming Language. An empty vector can be created by simply not passing any value while creating a regular vector using the c() function.

Syntax:

c()

This will return NULL as an output.

Example:

# create an empty vector a
a=c()

# display it
print(a)

Output:

NULL

A nested empty vector can also be created in R programming language.

Example:

# create an empty nested
# vector a
a=c(c(),c())

# display it
print(a)

Output:

NULL

Adding values to an empty vector

Method 1: Using range

We can use range (:) operator to add elements to an empty vector

Syntax:

start_value:end_value

Example:

# create an empty vector a
a=c()

# display it
print(a)

# adding numbers from 1 to 
# 20 to a vector
a=1:20

# display a
print(a)

Output:

NULL
 [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20

Method 2: Using another vector

For this a vector is first created empty and then a vector is assigned to it.

Example: 

# create an empty vector a
a=c()

# display it
print(a)

# adding names to vector which 
# is empty
a=c('sravan','bobby','rohith','gnnaesh','gajji')

# display a
print(a)

Output:

NULL
[1] "sravan"  "bobby"   "rohith"  "gnnaesh" "gajji"  

Method 3: Using index

We can assign/fill values in an empty vector by using "[]" operator which is known as the index operator

Syntax:

vector_name[index_location]=data

where, vector_name is the name of the empty vector which is created

• Index_location is the index value where particular element is located
• Data is the value which is assigned to particular index location

Example 1:

# create an empty numeric
# vector a
a=c()

# display it
print(a)

# create an empty numeric
# vector b
b=c()

# display it
print(b)

# create an empty numeric
# vector d
d=c()

# display it
print(d)

# include numeric data into 
# vector a insert value 10 
# at location 1
a[1]=10

# insert value 20 at location 2
a[2]=20

# insert value 14.5 at location 3
a[3]=14.5

# insert value 89.000 at location 4
a[4]=89.000

# display vector a
print(a)

# include logical data into vector
# b at locations 1,2,3
b[1]=TRUE
b[2]=FALSE
b[3]=FALSE

# display vector b
print(b)

# include character data into vector 
# d at locations 1,2,3
d[1]="Sravan"
d[2]="Bobby"
d[3]="pinkey"

# display vector
print(d)

Output:

NULL
NULL
NULL
[1] 10.0 20.0 14.5 89.0
[1]  TRUE FALSE FALSE
[1] "Sravan" "Bobby"  "pinkey"

We can insert all types of vectors in one empty vector.

Example 2:

# create an empty numeric
# vector a
a=c()

# display it
print(a)


# include all type of vector  
# data into vector a
a[1]="sravan"
a[2]=20
a[3]=14.5
a[4]=FALSE

# display vector a
print(a)

Output:

NULL
[1] "sravan" "20"     "14.5"   "FALSE" 

Method 4: Using append()

We can add data by using the append() function.

Syntax:

append(vector_name,value)

Where, vector_name is the name of the vector and value is the input value.

Example:

# create an empty numeric
# vector a
a=c()

# display it
print(a)

# append 10 using append() 
# function
a=append(a,10)

# display
print(a)

Output:

NULL
[1] 10

We can also append multiple data using c() function

Syntax:

append(vector,c(value1,value2,.value n))

Example:

# create an empty numeric
# vector a
a=c()

# display it
print(a)

# append 10 elements from 1 to 
# 10  using append() function
a=append(a,c(1:10))

# display
print(a)

Output:

NULL
 [1]  1  2  3  4  5  6  7  8  9 10