[R] RODBC connection - mixed data types

[Petr Pikal]

On 14 Aug 2001, at 16:49, Prof Brian D Ripley wrote:

> On Tue, 14 Aug 2001, Petr Pikal wrote:
> 
> > Dear R users
> >
> > I use R (1.3.0) Windows version usually with connection to Excel
> > sheets via RODBC Version: 0.8-2. Everything is OK until I use mixed
> > data types (numeric and character) in one column.
> 
> You can't have different data types in one column of a data frame. 
I know. I  have read the documentation. But I wonder if I can coerce 
transported data to stay same as they appear in Excel sheet, let say as 
a columns of characters.
You
> are not telling us what you are doing (at all: not a single command
> you used), but I suspect you need to know about as="matrix", which
> will import the data as a character matrix for you.

Here are the commands I use with some sample data
> 
> ppp_sqlQuery(con,"select * from [test$]")
> ppp
  vzor     x     y     z tep
1  110 51.24 20.26 11.87  ac
2  110 51.34 20.42 11.90  ab
3  110 49.77 22.05 11.42  NA
4   NA 49.84 19.30  7.43  ac
5   NA 49.88 19.32  7.50  ab
6   NA 49.76 18.11  4.49  NA
> ppp_sqlQuery(con,"select * from [test$]", as = "matrix")
> ppp
     vzor    x       y       z       tep 
[1,] "110.0" "51.24" "20.26" "11.87" "ac"
[2,] "110.0" "51.34" "20.42" "11.9"  "ab"
[3,] "110.0" "49.77" "22.05" "11.42" "NA"
[4,] "NA"    "49.84" "19.3"  "7.43"  "ac"
[5,] "NA"    "49.88" "19.32" "7.5"   "ab"
[6,] "NA"    "49.76" "18.11" "4.49"  "NA"

In Excel first column data was TP400 and in third column there was 
number 12 instead of NA. Adding as.is = TRUE doesn't make any 
difference. 

Most probably I will need to check consistency of my data directly in 
Excel before making a connection and transferring them to R.

Thanks

Petr Pikal
Precheza a.s.
Nabr.Dr.E.Benese 24
tel: 00420 641 25 2257
     +420 (0)724 008 364
     petr.pikal at precheza.cz
     p.pik at volny.cz

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