R programming language, where clause

1
votes

Within the R programming language, is it possible to use a where clause within ggplot? If not, then within the R language to allow me to use a where clause? For example, using the diamonds table can I only select records that the cut = "Good". Cut is a field in the Diamond table. The Cut field can equal "Fair", "Good", Very Good", "Premium", and "Ideal". 

diamonds[1:5,]
#   carat     cut   color  clarity    depth  table   price         x    y    z
# 1  0.23   Ideal       E      SI2     61.5     55     326      3.95 3.98 2.43

I want to use some type of conditional statement against a CSV read file. But to keep my example simple, I using the diamond table as a typical example of my problem. I want to filter cut = "Good" but to include fields related to the records = "Good".

Thank you for any help to my question.

1
r
what about ggplot(subset(diamonds,cut=="Good")) + ... ? – Ben Bolker
if you prefer SQL syntax you might look at the sqldf package. – Ben Bolker
just don't use "where," it is not needed. the bigger picture is that you need subset methods which r has in spades: subset,[,[[,$, etc – rawr

1 Answers

7
votes

You can use the subset function to filter rows from a data frame:

goodDiamods <- subset(diamonds, cut=='Good')

Check: Quick-R: Subsetting data

Another option is to use the sqldf package, and write a "query-like" expression:

library(sqldf)
goodDiamonds <- sqldf("select * from diamonds where cut='Good'")