R - Creating New Column Based off of a Partial String

问题

I have a large dataset (Dataset "A") with a column Description which contains something along the lines "1952 Rolls Royce Silver Wraith" or "1966 Holden".

I also have a separate dataset (Dataset "B") with a list of every Car Brand that I need (eg "Holden", "Rolls Royce", "Porsche").

How can I create a new column in dataset "A" that assigns the Partial strings of the Description with the correct Car Brand?

(This column would only hold the correct Car Brand with the appropriate matching cell).

Thank you.

Description New Column 1971 Austin 1300 Austin

回答1:

A solution from the tidyverse

A <- data.frame (Description = c("1970 Austin"), 
                 stringsAsFactors = FALSE)

B <- data.frame (Car_Brand = c("Austin"), 
                 stringsAsFactors = FALSE)

library(tidyverse)
A %>% mutate( New_Column= str_match( Description, B$Car_Brand)[,1] )

#   Description New_Column
# 1 1970 Austin     Austin

来源：https://stackoverflow.com/questions/52618671/r-creating-new-column-based-off-of-a-partial-string