[R] How to read a row dataset one by one

Henrik Bengtsson hb at maths.lth.se
Fri Jun 10 13:00:44 CEST 2005


Jan,

I'm not sure what you asking for.  First, you cannot make read.table() 
to output verbose message at every line read.  Second, if you have 
trouble to read you file, which looks like what you are showing, then 
read ?read.table carefully.  Most likely you wish to add argument 
header=TRUE and sep="\t" (if it is a tab-delimited file).

/Henrik

Jan Sabee wrote:
> For Henrik and Clark, thanks for your help.
> Then If I load to dataframe,
> MM16 <- read.table("G:\\Stuff\\data\\MM16.txt")
> MM16
> x1 x2 x3 x4 x5   y
> a  b  a  c  c    M1
> c  b  b  c  c    M4
> c  c  a  c  c    M2
> c  a  c  a  a    M2
> c  c  a  a  a    M1
> c  a  b  c  a    M3
> c  c  a  b  c    M3
> c  a  c  a  b    M2
> c  c  a  b  a    M1
> 
> How can I do it.
> Thanks again for your help.
> Jan Sabee
> 
> On 6/10/05, Henrik Bengtsson <hb at maths.lth.se> wrote:
> 
>>Open a connection a read line by line from that one, e.g.
>>
>>myReadPrint <- function(pathname, ...) {
>>   con <- file(pathname, open="r")
>>   on.exit(close(con)) # Guarantees to close connection!
>>
>>   count <- 0;
>>   while(TRUE) {
>>     line <- scan(con, sep="\t", nlines=1, fill=TRUE,
>>                                        quiet=TRUE, what="raw");
>>     # Alternatively, just...
>>     # line <- readLines(con, n=1)
>>     if (length(line) == 0)
>>       break;
>>     count <- count + 1;
>>     cat("read row no ", count, ",\n", sep="");
>>     print(line);
>>   }
>>}
>>
>>See ?file for more details.
>>
>>/Henrik
>>
>>Clark Allan wrote:
>>
>>>use a loop associated with the scan function.
>>>
>>>for (i in 1:9)
>>>{
>>>
>>>print(scan(file="c:/a.txt",sep="\t",skip=i,nlines=1,fill=T,quiet=T,what="raw"))
>>>}
>>>
>>>
>>>this works but there has to be a better solution
>>>
>>>
>>>
>>>Jan Sabee wrote:
>>>
>>>
>>>>Dear all,
>>>>How to read a row dataset one by one and then print it.
>>>>
>>>>x1 x2 x3 x4 x5   y
>>>>a  b  a  c  c    M1
>>>>c  b  b  c  c    M4
>>>>c  c  a  c  c    M2
>>>>c  a  c  a  a    M2
>>>>c  c  a  a  a    M1
>>>>c  a  b  c  a    M3
>>>>c  c  a  b  c    M3
>>>>c  a  c  a  b    M2
>>>>c  c  a  b  a    M1
>>>>
>>>>I need a result like
>>>>read row no 1,
>>>>[1] a  b  a  c  c    M1
>>>>read row no 2,
>>>>[1] c  b  b  c  c    M4
>>>>.
>>>>.
>>>>.
>>>>the last row,
>>>>[1] c  c  a  b  a    M1
>>>>
>>>>Kind regards,
>>>>Jan Sabee
>>>>
>>>>______________________________________________
>>>>R-help at stat.math.ethz.ch mailing list
>>>>https://stat.ethz.ch/mailman/listinfo/r-help
>>>>PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>>>>
>>>>
>>>>------------------------------------------------------------------------
>>>>
>>>>______________________________________________
>>>>R-help at stat.math.ethz.ch mailing list
>>>>https://stat.ethz.ch/mailman/listinfo/r-help
>>>>PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>>
>>
> 
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