How to check if a character column only contains alphabets in R data frame?

To check if a character column only contains alphabets in R data frame, we can follow the below steps −

• First of all, create a data frame with a character column.
• Then, use grepl function to check if all the values in the column contains only alphabets.

Example 1

Let's create a data frame as shown below −

 Live Demo

x<-sample(c("India","UK","USA","Japan","China2"),20,replace=TRUE)
df1<-data.frame(x)
df1

On executing, the above script generates the below output(this output will vary on your system due to randomization) −

   x
1 India
2 USA
3 China2
4 USA
5 Japan
6 UK
7 China2
8 Japan
9 USA
10 Japan
11 Japan
12 Japan
13 Japan
14 India
15 Japan
16 UK
17 India
18 UK
19 India
20 USA

Check whether data frame column contains only alphabets

Using grepl function to check whether column x contains values only having alphabets −

 Live Demo

x<-sample(c("India","UK","USA","Japan","China2"),20,replace=TRUE)
df1<-data.frame(x)
grepl("^[A-Za-z]+$",df1$x)

Output

[1] TRUE TRUE FALSE TRUE TRUE TRUE FALSE TRUE TRUE TRUE TRUE TRUE
[13] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE

Example2

Let’s create a data frame as shown below −

 Live Demo

y<-sample(c("1","23","14","11","1F","3"),20,replace=TRUE)
df2<-data.frame(y)
df2

On executing, the above script generates the below output(this output will vary on your system due to randomization) −

   y
1  11
2  1F
3  1
4  11
5  23
6  1F
7  11
8  23
9  14
10 14
11 1F
12 14
13 1F
14 11
15 1
16 23
17 1F
18 1
19 3
20 23

Check whether data frame column contains only alphabets

Using grepl function to check whether column y contains values only having alphabets −

 Live Demo

y<-sample(c("1","23","14","11","1F","3"),20,replace=TRUE)
df2<-data.frame(y)
grepl("^[A-Za-z]+$",df2$y)

Output

[1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[13] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE

Nizamuddin Siddiqui

Updated on 13-Aug-2021 10:51:44

• Related Questions & Answers
• How to check if a data frame column contains duplicate values in R?
• Check if a string contains only alphabets in Java using Regex
• How to check if a string contains only one type of character in R?
• How to check if an R matrix column contains only duplicate values?
• Check if a string contains only alphabets in Java using Lambda expression
• Check if a string contains only alphabets in Java using ASCII values
• How to check if a column is categorical in R data frame?
• How to remove a character in an R data frame column?
• How to check if a variable contains number greater than 1 in an R data frame?
• How to convert alphabets to numbers in R data frame?
• How to associate a character to numbers in an R data frame column?
• How to convert a character data frame to numeric data frame in R?
• How to check whether a column exists in an R data frame?
• How to check if a string contains only decimal characters?
• How to check if a Python string contains only digits?