R help - Jul 2005 - not supressing leading zeros when reading a table?

Dear R list,

I have a dataset with a column which should be read as character, like this:

  name surname answer
1 xx   yyy     "00100"
2 rrr  hhh     "01"

When reading this dataset with read.table, I get
1 xx   yyy     100
2 rrr  hhh     1

The string column consists in answers to multiple choice questions, not all 
having the same number of answers. I could format the answers using formatC but 
there are over a hundred different questions in there.

I tried with quote="\"'" without any luck. Googling after
this take me nowhere
either. It should be simple but I seem to miss it...
Can anybody point me to the right direction?

TIA,
Adrian

On Sun, 2005-07-10 at 18:13 +0000, Adrian Dusa wrote:
> Dear R list,
> 
> I have a dataset with a column which should be read as character, like
this:
> 
>   name surname answer
> 1 xx   yyy     "00100"
> 2 rrr  hhh     "01"
> 
> When reading this dataset with read.table, I get
> 1 xx   yyy     100
> 2 rrr  hhh     1
> 
> The string column consists in answers to multiple choice questions, not all
> having the same number of answers. I could format the answers using formatC
but
> there are over a hundred different questions in there.
> 
> I tried with quote="\"'" without any luck. Googling
after this take me nowhere
> either. It should be simple but I seem to miss it...
> Can anybody point me to the right direction?
> 
> TIA,
> Adrian
With your example data saved in a file called "test.txt":
> df <- read.table("test.txt", header = TRUE, colClasses =
"character")
> df
  name surname answer
1   xx     yyy  00100
2  rrr     hhh     01
> str(df)
`data.frame':	2 obs. of  3 variables:
 $ name   : chr  "xx" "rrr"
 $ surname: chr  "yyy" "hhh"
 $ answer : chr  "00100" "01"


See the colClasses argument in ?read.table.

HTH,

Marc Schwartz

Adrian Dusa wrote:
> Dear R list,
> 
> I have a dataset with a column which should be read as character, like
this:
> 
>   name surname answer
> 1 xx   yyy     "00100"
> 2 rrr  hhh     "01"
> 
> When reading this dataset with read.table, I get
> 1 xx   yyy     100
> 2 rrr  hhh     1
> 
> The string column consists in answers to multiple choice questions, not all
> having the same number of answers. I could format the answers using formatC
but
> there are over a hundred different questions in there.
> 
> I tried with quote="\"'" without any luck. Googling
after this take me nowhere
> either. It should be simple but I seem to miss it...
> Can anybody point me to the right direction?
By default, read.table guesses about the column type. Yours looks 
numeric, even though it is not.

Use the colClasses argument of read.table to specify the column type. 
If you only have the 3 columns above, colClasses="character" should
work.

Duncan Murdoch

Adrian,

To prevent coercion to numeric, try:

mydata <- read.table("myfile", colClasses="character")

HTH.

alejandro
On 7/10/05, Adrian Dusa <dusa.adrian at gmail.com>
wrote:
> Dear R list,
> 
> I have a dataset with a column which should be read as character, like
this:
> 
>   name surname answer
> 1 xx   yyy     "00100"
> 2 rrr  hhh     "01"
> 
> When reading this dataset with read.table, I get
> 1 xx   yyy     100
> 2 rrr  hhh     1
> 
> The string column consists in answers to multiple choice questions, not all
> having the same number of answers. I could format the answers using formatC
but
> there are over a hundred different questions in there.
> 
> I tried with quote="\"'" without any luck. Googling
after this take me nowhere
> either. It should be simple but I seem to miss it...
> Can anybody point me to the right direction?
> 
> TIA,
> Adrian
> 
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