[R] Blanking out specific cells in a data frame

[Sabatier, Jennifer F. (CDC/OID/NCHHSTP)]

Hi Ista,

Thanks a lot for your response.  It looks like the solution Stefan
suggested is the same as you are and it works great.  

I do know that you can't actually have unequal column lengths.  The
reality is I am creating a pretty table to export to EXCEL and it
contains some summary statistics as well as the information from a
chi-square test (test stat, df, pvalue).  When I added the info from the
chi-square test to the data frame it populated all the rows and I just
wanted to know how to blank them out.

Now that I have Stefan's solution, which turns all the un-needed info
into NAs I can use NAToUnkown() to blank them out completely.

Thanks, again, for getting back to me!

Jen



-----Original Message-----
From: Ista Zahn [mailto:istazahn at gmail.com] 
Sent: Wednesday, May 19, 2010 1:59 PM
To: r-help at r-project.org
Cc: Sabatier, Jennifer F. (CDC/OID/NCHHSTP)
Subject: Re: [R] Blanking out specific cells in a data frame

Hi Jen,
You cannot have a dataframe with unequal column lengths, so you have two

options (well maybe more, but two that come to mind): set the values to 
missing instead of deleting them, or store your data in a list instead
of a 
data frame.

For option 1 (recommended) all you need is
mydf[-1, 6] <- NA

Best,
Ista
On Wednesday 19 May 2010 1:36:50 pm Sabatier, Jennifer F.
(CDC/OID/NCHHSTP) 
wrote:
> Hi R-Help,
> 
> I am a new R user.  I have used SAS for many years (just FYI on what I
> am used to and possible obstacles it presents).
> 
> I have a data frame:
> 
> mydf <-data.frame(matrix(rnorm(102), ncol=6)
> 
> I would like to be able to delete ALL the information in column 6 for
> rows 2 through r, where r=#rows.
> 
> How can I do that?
> 
> I want the resulting data frame to look like this:
> 
> X1	X2	X3	X4	X5	X6
> Data	data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> Data	data	data	data	data
> 
> 
> (Sorry for using the word "data" and not having a cut and paste of my
> actual data frame...the computer I am writing this email on does not
> have R so I have to improvise.)
> 
> Thanks,
> 
> Jen
> 
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