[R] Excel files

[Gabor Grothendieck]

Just a minor correction and a simplification.   The header=T
is missing from read.table and as.is=1:2 could be added to
avoid having to use as.character in chron.  Also in your data
(but not in Grace's) the default chron format is used so the
format specifier can be omitted:

require(chron)
x <- read.table("clipboard", header=T, as.is=1:2)
timedate <- chron( x$date, x$time )
plot( x$Value~timedate, pch=as.numeric(x$Sex) )



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Date:   Sun, 7 Mar 2004 19:43:49 -0600 
From:   Robert W. Baer, Ph.D. <rbaer at atsu.edu>
[ Add to Address Book | Block Address | Report as Spam ] 
To:   <R-help at stat.math.ethz.ch> 
Cc:   Grace Conlon <gracestat at yahoo.com> 
Subject:   Re: [R] Excel files 

 
This might get you started on reading and plotting the dates and times for
levels of a gender factor:
# I assume the following Excel data
date time Sex Value
1 5/5/1999 10:00:00 male 14.987685
2 7/3/1998 20:00:00 female 17.667527
3 8/6/1999 3:23:00 male 3.428401
4 12/7/1997 6:36:00 male 14.977503
5 3/4/2004 9:49:00 male 6.704703
6 11/15/1999 23:04:00 female 5.536046
7 10/16/1998 6:05:00 male 12.153291
8 2/5/1999 3:06:00 female 12.121168
9 3/3/1997 3:07:00 male 4.641686
10 8/6/2004 7:08:00 male 6.649273
11 8/7/1999 22:10:00 male 11.158278
12 7/4/1998 21:11:00 female 8.098113
13 7/6/1999 5:15:00 male 6.220476
14 9/1/1997 6:16:00 female 1.939658
15 3/15/2004 7:05:00 male 2.032969
16 5/16/1999 2:23:00 male 16.436000
#Simulate Excel read
x<-read.table("clipboard")
x

# Do your plotting
library(chron)
timedate=chron(as.character(x$date),as.character(x$time),format=c(dates="m/d/y",times="h:m:s"))
plot(x$Value~timedate,pch=as.numeric(x$Sex))

1. How can I access the data of certain column? I mean how can I refer it in
R?
Notice how the read in data is in a dataframe. To access a given column of
the data frame use a $ plus the column name.
2. How can I make the two column character values(the time variable I
mentioned) to the X ases values?
see the construction of timedate
3. If I have three variables, one is y axes, one is x axes, the third one
is a logic var, how can I make the logic varaible on the plot also?
I don't know precisely what you want but see how I show gender using the
pch= tag to get different plot symbols. The details depend what you want
here.


HTH,

Rob Baer
----- Original Message ----- 
From: "Grace Conlon" <gracestat at yahoo.com>
To: <R-help at stat.math.ethz.ch>
Sent: Sunday, March 07, 2004 5:43 PM
Subject: [R] Excel files


Hello,

I was trying to import data from an Excel file. After I imported the data, I
was trying to make a scatter plot.

The X axes variable is a time variable, which occupies two columns, one is
date, another one is time. Example 21-Apr-03, 4:10 PM. My qestion is:


4. I have a column of number values, however I want to creat a new column,
the value of each cell is the average of every 10 values of the first
column. How can I do it in R?

I tried to figure it out in the help section, however, it spent me a lot of
times, I still can not get the way out, please help. THank you!