String and Class in R

 LEVELS:Displays levels of each variable in the data

TABLE:Display the count of each levels present in the data

EMPLOYEE       PERFORMANCE

RAM                      VG (Very good)

SAMANYU             G  (Good)

JACK                     EXC(Excellence)

JILL                        VG (Very good)

JONE                     EXC (Excellence)

LEVELS:3(EXC,VG,G)

TABLE:EXC=2,VG=2,G=1

str:displays the datatype of each variable in the data

class:dataframe

Example: lp.csv 

Name  Age  Marks 

surya  29     98 

sivi   10      23 

somu  24    99

bapu  26    80

jack  47     89 

jone  34     79

solution: 

data1<-read.csv("lp.csv)

levels(data1$Marks)

table(data1$Marks)

str(data1)

class(data1)