R help - Aug 2010 - a question about 'read.table' with or without 'read.table'.(urgent)

Hi, I've got a quite tricky question.
I have a txt file, named 'temp.txt', as the following:
snp1        snp2        snp3
AA           00           00
GG           GG           00
00           AA           00

I want to read the file into R. 
1) when I use 'read.table' without 'header=T'
option,
> temp <- read.table('temp.txt')
# I got 
> temp
    V1   V2   V3
1 snp1 snp2 snp3
2   AA   00   00
3   GG   GG   00
4   00   AA   00

2) If I include the 'header=T' option,
> temp <- read.table('temp.txt', header=T, as.is=T)
# I got
> temp
  snp1 snp2 snp3
1   AA   00    0
2   GG   GG    0
3   00   AA    0

The difference is for 'snp3', we can see, in 1) the values for snp3 are
all
'00', while in 2) the values are all '0'.     How can I keep the
original
values for snp3 as '00', meanwhile get the 'headers' or say the
colnames as
'snp1        snp2        snp3'?

thank you very much,

karena

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read.table("temp.txt",header=T,colClasses = "character")

-----
A R learner.
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I believe Wu Gong has given you a solution.  As a note you were probably reading
in the first two columns as either factors or characters and the last one as
numeric.  You might want to try it again and then do a str() on the resulting
data.frame to see what was happening.

It can be confusing to discover that you have factor rather than character data
in the data.frame.  :)

--- On Thu, 8/5/10, karena <dr.jzhou at gmail.com> wrote:
> From: karena <dr.jzhou at gmail.com>
> Subject: [R] a question about 'read.table' with or without
'read.table'.(urgent)
> To: r-help at r-project.org
> Received: Thursday, August 5, 2010, 12:32 AM
> 
> Hi, I've got a quite tricky question.
> I have a txt file, named 'temp.txt', as the following:
> snp1? ? ? ? snp2? ? ?
> ? snp3
> AA? ? ? ? ???00?
> ? ? ? ???00
> GG? ? ? ? ???GG?
> ? ? ? ???00
> 00? ? ? ? ???AA?
> ? ? ? ???00
> 
> I want to read the file into R. 
> 1) when I use 'read.table' without 'header=T' option,
> > temp <- read.table('temp.txt')
> # I got 
> > temp
> ? ? V1???V2???V3
> 1 snp1 snp2 snp3
> 2???AA???00???00
> 3???GG???GG???00
> 4???00???AA???00
> 
> 2) If I include the 'header=T' option,
> > temp <- read.table('temp.txt', header=T, as.is=T)
> # I got
> > temp
> ? snp1 snp2 snp3
> 1???AA???00? ? 0
> 2???GG???GG? ? 0
> 3???00???AA? ? 0
> 
> The difference is for 'snp3', we can see, in 1) the values
> for snp3 are all
> '00', while in 2) the values are all '0'.?
> ???How can I keep the original
> values for snp3 as '00', meanwhile get the 'headers' or say
> the colnames as
> 'snp1? ? ? ? snp2? ? ?
> ? snp3'?
> 
> thank you very much,
> 
> karena
> 
> -- 
> View this message in context:
http://r.789695.n4.nabble.com/a-question-about-read-table-with-or-without-read-table-urgent-tp2314423p2314423.html
> Sent from the R help mailing list archive at Nabble.com.
> 
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