How to create a data frame with numeric and character columns?

Question

I'm trying to build a data frame consisting of three character variables and one numeric variable. When I run the following code, I get a four-column matrix, but the score variable is no longer numeric, and the scores are treated as factors.

school<-c("NYU", "BYU", "USC", "FIT", "UNH","UCLA","USF","Columbia")
state<-c("NY","UT","CA","NY","NY","CA", "CA","NY")
measure<-c("MSAT","MSAT","GPA","MSAT","MSAT","GPA","GPA","GPA")
score<-c(500, 490, 2.9, 759, 550, 1.2, 3.1, 3.2)
data<-cbind(school,state, measure,score)

If I run

data1<-data.frame(cbind(school,state, measure,score))

I get a data frame where score is still a factor. How can I build this data frame so that score is numeric?

Answer 1

To build a data frame consisting of three character variables and one numeric variable, you need to specify: stringsAsFactors=FALSE in data.frame() function:

school<-c("NYU", "BYU", "USC")
state<-c("NY","UT","CA")
measure<-c("MSAT","MSAT","GPA")
score<-c(500, 490, 2.9)
df<-data.frame(school,state, measure,score,  stringsAsFactors=FALSE)

Here's the result:

summary(df)
school             state             measure              score      
Length:3           Length:3           Length:3           Min.   :  2.9  
Class :character   Class :character   Class :character   1st Qu.:246.4  
Mode  :character   Mode  :character   Mode  :character   Median :490.0  
                                                         Mean   :331.0  
                                                         3rd Qu.:495.0  
                                                         Max.   :500.0