· r-2 rstats

R: Deriving a new data frame column based on containing string

I've been playing around with R data frames a bit more and one thing I wanted to do was derive a new column based on the text contained in the existing column.

I started with something like this:


> x = data.frame(name = c("Java Hackathon", "Intro to Graphs", "Hands on Cypher"))
> x
             name
1  Java Hackathon
2 Intro to Graphs
3 Hands on Cypher

And I wanted to derive a new column based on whether or not the session was a practical one. The grepl function seemed to be the best tool for the job:


> grepl("Hackathon|Hands on|Hands On", x$name)
[1]  TRUE FALSE  TRUE

We can then add a column to our data frame with that output:


x$practical = grepl("Hackathon|Hands on|Hands On", x$name)

And we end up with the following:


> x
             name practical
1  Java Hackathon      TRUE
2 Intro to Graphs     FALSE
3 Hands on Cypher      TRUE

Not too tricky but it took me a bit too long to figure it out so I thought I'd save future Mark some time!

  • LinkedIn
  • Tumblr
  • Reddit
  • Google+
  • Pinterest
  • Pocket