We can perform any type of data manipulation to an R data frame either in memory or during import. The following example shows the selection of a portion of the iris dataset using the sqldf package:
# Selecting the rows from iris dataset where sepal length > 2.5
# and store that in subiris data frame
library(sqldf)
subiris<- sqldf("select * from iris where Sepal_Width> 3")
head(subiris)
Sepal_Length Sepal_Width Petal_Length Petal_Width Species
1 5.1 3.5 1.4 0.2 setosa
2 4.7 3.2 1.3 0.2 setosa
3 4.6 3.1 1.5 0.2 setosa
4 5.0 3.6 1.4 0.2 setosa
5 5.4 3.9 1.7 0.4 setosa
6 4.6 3.4 1.4 0.3 setosa
nrow(subiris)
[1] 67We can also select a smaller number of columns while filtering out some of the rows with a specified condition. The following example...