-----------------------------------
  R INTRODUCTION PART II
-----------------------------------

In this session, we will get introduced to R commands for inputting data and
outputting R output and graphs.

	scan command

	data.entry command

	read.table command

	saving output

	saving graphs

# There are several convenient ways of getting data into R.

# INPUTTING DATA FROM THE KEYBOARD:

# For small datasets, one can type the data directly into R using the scan command.

# Just type 

mydata=scan()

# and enter the numbers, one or more on a line, and type a blank line when you are 
# finished.

# Here's an example, entering in the temperatures 45, 55, 65, 23, 33.  I type
# temps at the end to verify that the data has been entered in correctly.

> temps=scan()
1: 45
2: 55 65
4: 23
5: 33
6: 
Read 5 items
> temps
[1] 45 55 65 23 33

# Another convenient way of entering data is by the data.entry command, where you
# enter data by a spreadsheet format

# First, you have to define the variable name that will hold the data.  This indicates
# that mydata contains one value that is missing (R uses NA for missing).

mydata=c(NA)

# Then you can type

data.entry(mydata)

# You'll see a spreadsheet window.  You enter data into the spreadsheet (replace the NA # entry with a number) and close the window # when you are done.

# READING IN SOME DATA INTO R FROM A FILE

# For larger data files, I recommend creating them in some program outside of R
# and then reading them into R using the read.table command.

# Here is a simple example:  I have the following data that I wish to enter into R:
# (the number of wins and losses for five baseball teams)

TEAM		WINS	LOSSES
Kansas City	54	43
Minnesota	49	49
Chicago		49	50
Cleveland	41	58
Detroit		26	71

# STEP 1:  I entered the data into Excel, the first row containing the variable names
# TEAM, WINS, LOSSES.

# STEP 2:  I save the data as a "text, tab-delimited" file -- I call the file winslosses.txt

# STEP 3:  You have to place the file in a location where R can read it.  R has a "working # directory" where it is looking for files.  You can change the working directory
# to the folder which contains the data file.

# STEP 4:  You read the data into R using the read.table command.  Note that we indicate in # the command that there is a header line with the column names.
 
 data=read.table("winslosses.txt",header=T)

# look at the data matrix

data

# SAVING R OUTPUT

# Here we describe several ways of saving R output.

# If you wish to save all or some of the output displayed in the R Console, then just
# select and copy the output and paste it into your favoriate word processor like Word.

# R also keeps track of all of the commands that you type in.  To save these commands,
# select Save History from the File menu and save this into a text file.

# You can also save graphs that are created using R using standard Copy commands.  We'll
# mention this again when we discuss graphing on R.

########## END OF R SESSION ###################