Split DataFrame Variable into Multiple Columns in R

In this article, we will discuss how to split dataframe variables into multiple columns using R programming language.

Method 1: Using do.call method

The strsplit() method in R is used to split the specified column string vector into corresponding parts. The pattern is used to divide the string into subparts. 

Syntax:

strsplit(str, pattern)

Parameter :

• str: The string vector to be split.
• pattern: Pattern to split up the string by.

The do.call() method is used to call a function from within a method name. The rbind() method can then be used to combine the columns obtained as vectors as a result of the application of strsplit method. 

Syntax:

do.call(what, args)

Parameter: 

• what - The function to execute
• args - Additional arguments to execute.

Example: Split Dataframe variable into multiple columns

# creating a dataframe 
data_frame <- data.frame(
                         col1 = c("val_1","val_2","val_3","val_4")
                         )
print("Original DataFrame")
print(data_frame)

# splitting values in column
print("Modified DataFrame")

# splitting the values of col1 using underscore character
data.frame(do.call("rbind", strsplit(as.character(data_frame$col1), "_",
                                     fixed = TRUE)))

Output:

[1] "Original DataFrame"
  col1
1 val_1
2 val_2
3 val_3
4 val_4
[1] "Modified DataFrame"
  X1 X2
1 val  1
2 val  2
3 val  3
4 val  4

Method 2: Using tidyr package

The tidyr package in R is used to mutate and visualize the data. It is used to tidy up the data. The package can be downloaded and installed into the working space using the following command:

install.packages("tidyr")

The separate method in R can be used to split up the specified string column or vector into corresponding sub-parts. The length of the second argument vector is equivalent to the number of pieces to split up the data into. 

Syntax:

separate(str, n, pattern)

Parameter:

• str: The string vector to be split.
• n: The names of pieces to split the string into.
• pattern: Pattern to split up the string by.

Example: Split dataframe variable into multiple columns 

library("tidyr")

# creating a dataframe 
data_frame <- data.frame(
                         col1 = c("val_1","val_2","val_3","val_4")
                         )

print("Original DataFrame")
print(data_frame)

# splitting values in column
print("Modified DataFrame")

data_frame %>%
  separate(col1, c("col1", "col2"), "_")

Output:

[1] "Original DataFrame"
  col1
1 val_1
2 val_2
3 val_3
4 val_4
[1] "Modified DataFrame"
 col1 col2
1  val    1
2  val    2
3  val    3
4  val    4

Method 3: Using stringr package

The stringr package in R is used to carry out string manipulations. It helps us perform modifications related to string. The package can be download and installed into the working space using the following command : 

install.packages("stringr")

The str_split_fixed method in stringr package is used to split up a string into a fixed number of pieces. The method transforms strings into the specified number of substrings. The specified pattern should be of unit length. 

Syntax:

str_split_fixed(str, pattern , n

Parameter : 

• str: The string vector to be split.
• pattern: Pattern to split up the string by.
• n: The number of pieces to split the string into.

Example: Split dataframe variable into multiple columns

library("stringr")

# creating a dataframe 
data_frame <- data.frame(
                         col1 = c("val_1","val_2","val_3","val_4")
                         )
print("Original DataFrame")
print(data_frame)

# splitting values in column
print("Modified DataFrame")
str_split_fixed(data_frame$col1, "_", 2)

Output:

[1] "Original DataFrame"
  col1
1 val_1
2 val_2
3 val_3
4 val_4
[1] "Modified DataFrame"
    [,1]  [,2]
[1,] "val" "1"
[2,] "val" "2"
[3,] "val" "3"
[4,] "val" "4"