1. Use the read.table() function to read the data in groupA.txt, groupB.txt, groupC.txt, groupD. txt in folder group and generate data.frame in the following format named Dat1 using two methods.The first act is to list names.

groupA.txt, groupB.txt, groupC.txt, groupD. txt like:

20

52

12

30

...

Finally, it looks like:

Value Group

12 group A

13 group A

13 group A

16 group A

14 group B

14 group B

18 group C