You can use the following methods to extract numbers from strings in R:

Method 1: Extract Number from String Using Base R

as.numeric(gsub("D", "", df$my_column))

Method 2: Extract Number from String Using readr Package

library(readr)

parse_number(df$my_column)

This tutorial explains how to use each method in practice with the following data frame:

#create data frame
df <- data.frame(team=c('A', 'A', 'A', 'B', 'B', 'B'),
                 position=c('Guard23', 'Guard14', '2Forward',
                            'Guard25', '6Forward', 'Center99'))

#view data frame
df

  team position
1    A  Guard23
2    A  Guard14
3    A 2Forward
4    B  Guard25
5    B 6Forward
6    B Center99

Example 1: Extract Number from String Using Base R

The following code shows how to extract the numbers from each string in the position column of the data frame:

#extract number from each string in 'position' column
as.numeric(gsub("D", "", df$position))

[1] 23 14  2 25  6 99

Notice that the numeric values have been extracted from each string in the position column.

Note: The gsub() function simply replaces all non-numbers ( D ) in a string with a blank space. This has the effect of extracting only the numbers from the string.

If you’d like, you can also store these numeric values in a new column in the data frame:

#create new column that contains numbers from each string in 'position' column
df$num <- as.numeric(gsub("D", "", df$position))

#view updated data frame
df

  team position num
1    A  Guard23  23
2    A  Guard14  14
3    A 2Forward   2
4    B  Guard25  25
5    B 6Forward   6
6    B Center99  99

Example 2: Extract Number from String Using reader Package

The following code shows how to extract the numbers from each string in the position column of the data frame by using the parse_number() function from the package:

library(readr)

#extract number from each string in 'position' column
parse_number(df$position)

[1] 23 14  2 25  6 99

This matches the results from using the gsub() function in base R.