Create a dummy variable for all rows that contain County in R-CodePudding

Given the following using R:

County_or_City <- c("Butte County", "Oroville", "Solano Cnty", "Redding", "Maripossa county")
data.frame(County_or_City)

    County_or_City
1     Butte County
2         Oroville
3      Solano Cnty
4          Redding
5 Maripossa county

I would like to create a new column with a dummy variable for rows that contain Cnty, County, or county. Sorry I know this is very basic, but I'm learning. What do I do???

CodePudding user response：

Using base R

transform(data.frame(County_or_City), 
 dummy = grepl('C(ou)?nty', County_or_City, ignore.case = TRUE))

-output

   County_or_City dummy
1     Butte County  TRUE
2         Oroville FALSE
3      Solano Cnty  TRUE
4          Redding FALSE
5 Maripossa county  TRUE

CodePudding user response：

Code

library(dplyr)
library(stringr)

county_words <- c("County","county","Cnty")

data.frame(County_or_City) %>% 
  mutate(dummy = str_detect(County_or_City,county_words))

Output

    County_or_City dummy
1     Butte County  TRUE
2         Oroville FALSE
3      Solano Cnty  TRUE
4          Redding FALSE
5 Maripossa county  TRUE

CodePudding user response：

In base R you could use grepl (which searches for patterns in strings and returns a boolean TRUE/FALSE) with paste and specify collapse = "|" (which means search for this "or" that term) to search for your terms and return a boolean (TRUE/FALSE) for each county, and then add * 1 to turn it into a dichotomous dummy variable (0 = FALSE/1 = TRUE):

County_or_City <- c("Butte County", "Oroville", "Solano Cnty", "Redding", "Maripossa county")
df <- data.frame(County_or_City)

srchtrms <- c("County","county","Cnty")

df$new <- grepl(paste(srchtrms, collapse = "|"), df$County_or_City) * 1
df

Output:

    County_or_City new
1     Butte County   1
2         Oroville   0
3      Solano Cnty   1
4          Redding   0
5 Maripossa county   1