R help - Mar 2003 - Convert char vector to numeric table

I'm a great fan of read.table(), but this time the data had a lot of cruft.
So I used readLines() and editted the char vector to eventually get something
like this:
"     23.4   1.5   4.2"
"     19.1   2.2   4.1"
and so on. To get that into a 3 col numeric table, I first just used:

writeLines(data,"tempfile")
read.table("tempfile",col.names=c("A","B","C"))

Works fine, but writing to a temporary file seems ... inelegant?  And
read.table() doesn't take a char vector as a file or connection argument.
The following works but it seems like a lot of code:

data <- sub(" +","",data)   		# remove leading blanks for
strsplit
data <- strsplit(data," +")   		# strsplit returns a list of char
vectors
ndata <- character(0)			# vectorize the list of char vectors
for (ii in 1:length(data)) ndata <- c(ndata,data[[ii]])  
ndata <- as.numeric(ndata)				
dim(ndata) <- c(3,length(data))	  	
data <- t(ndata)
data.frame(A=data[,1],B=data[,2],C=data[,3])

Am I missing something?

Thanks,
Bruce L.

Nurnberg-LaZerte wrote:
> I'm a great fan of read.table(), but this time the data had a lot of
cruft. So I used readLines() and editted the char vector to eventually get
something like this:
> "     23.4   1.5   4.2"
> "     19.1   2.2   4.1"
> and so on. To get that into a 3 col numeric table, I first just used:
> 
> writeLines(data,"tempfile")
>
read.table("tempfile",col.names=c("A","B","C"))
> 
> Works fine, but writing to a temporary file seems ... inelegant?  And
read.table() doesn't take a char vector as a file or connection argument.
The following works but it seems like a lot of code:
> 
> data <- sub(" +","",data)   		# remove leading
blanks for strsplit
> data <- strsplit(data," +")   		# strsplit returns a list of
char vectors
> ndata <- character(0)			# vectorize the list of char vectors
> for (ii in 1:length(data)) ndata <- c(ndata,data[[ii]])  
> ndata <- as.numeric(ndata)				
> dim(ndata) <- c(3,length(data))	  	
> data <- t(ndata)
> data.frame(A=data[,1],B=data[,2],C=data[,3])
> 

Bruce,
   I don't know if this is any more elegant, but...

data <- c("     23.4   1.5   4.2","     19.1   2.2  
4.1")
data.new <- as.data.frame(t(sapply(strsplit(gsub("[ \t]*","
",data),"
"),as.numeric))[,-1])
names(data.new) <- LETTERS[1:3]


Sundar

Have you considered something like the following:

 > tst <- c("     23.4   1.5   4.2", "     19.1   2.2  
4.1")
 > num1 <- regexpr("[0-9]", tst)
 > tst1 <- substring(tst, num1)
 > b1 <- regexpr(" ", tst1)
 > x1 <- as.numeric(substring(tst1, 1, num1))
 > tst <- substring(tst1, b1)
 > x1; tst
[1] 23.4 19.1
[1] "   1.5   4.2" "   2.2   4.1"

You can put this in a loop with appropriate modification for the end of 
the strings, etc.

Will this solve your problems?
Best Wishes,
Spencer Graves

Nurnberg-LaZerte wrote:
> I'm a great fan of read.table(), but this time the data had a lot of
cruft. So I used readLines() and editted the char vector to eventually get
something like this:
> "     23.4   1.5   4.2"
> "     19.1   2.2   4.1"
> and so on. To get that into a 3 col numeric table, I first just used:
> 
> writeLines(data,"tempfile")
>
read.table("tempfile",col.names=c("A","B","C"))
> 
> Works fine, but writing to a temporary file seems ... inelegant?  And
read.table() doesn't take a char vector as a file or connection argument.
The following works but it seems like a lot of code:
> 
> data <- sub(" +","",data)   		# remove leading
blanks for strsplit
> data <- strsplit(data," +")   		# strsplit returns a list of
char vectors
> ndata <- character(0)			# vectorize the list of char vectors
> for (ii in 1:length(data)) ndata <- c(ndata,data[[ii]])  
> ndata <- as.numeric(ndata)				
> dim(ndata) <- c(3,length(data))	  	
> data <- t(ndata)
> data.frame(A=data[,1],B=data[,2],C=data[,3])
> 
> Am I missing something?
> 
> Thanks,
> Bruce L.
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help

use 'textConnection':
> x.1 <- c('1 2 3','4 5 6','7 8 9','8 7
6','6 5 4')   # create character
vector
> x.in <- textConnection(x.1) # setup connection
> x.data <- read.table(x.in)  # read in the character vector
> x.data
  V1 V2 V3
1  1  2  3
2  4  5  6
3  7  8  9
4  8  7  6
5  6  5  4
>



                      "Nurnberg-LaZerte"
                      <mail at fwr.on.ca>             To:      
"R's help mailing list" <r-help at stat.math.ethz.ch>
                      Sent by:                     cc:
                      r-help-bounces at stat.m        Subject:  [R] Convert char
vector to numeric table
                      ath.ethz.ch


                      03/31/03 17:09
                      Please respond to
                      Nurnberg-LaZerte






I'm a great fan of read.table(), but this time the data had a lot of cruft.
So I used readLines() and editted the char vector to eventually get
something like this:
"     23.4   1.5   4.2"
"     19.1   2.2   4.1"
and so on. To get that into a 3 col numeric table, I first just used:

writeLines(data,"tempfile")
read.table("tempfile",col.names=c("A","B","C"))

Works fine, but writing to a temporary file seems ... inelegant?  And
read.table() doesn't take a char vector as a file or connection argument.
The following works but it seems like a lot of code:

data <- sub(" +","",data)                        # remove
leading blanks
for strsplit
data <- strsplit(data," +")                            # strsplit
returns a
list of char vectors
ndata <- character(0)                                  # vectorize the list
of char vectors
for (ii in 1:length(data)) ndata <- c(ndata,data[[ii]])
ndata <- as.numeric(ndata)
dim(ndata) <- c(3,length(data))
data <- t(ndata)
data.frame(A=data[,1],B=data[,2],C=data[,3])

Am I missing something?

Thanks,
Bruce L.

______________________________________________
R-help at stat.math.ethz.ch mailing list
https://www.stat.math.ethz.ch/mailman/listinfo/r-help




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Use a file() connection (no argument) or a textConnection.

file() is a powerful tool, often overlooked.

On Mon, 31 Mar 2003, Nurnberg-LaZerte wrote:
> I'm a great fan of read.table(), but this time the data had a lot of
cruft. So I used readLines() and editted the char vector to eventually get
something like this:
> "     23.4   1.5   4.2"
> "     19.1   2.2   4.1"
> and so on. To get that into a 3 col numeric table, I first just used:
> 
> writeLines(data,"tempfile")
>
read.table("tempfile",col.names=c("A","B","C"))
> 
> Works fine, but writing to a temporary file seems ... inelegant?  And
read.table() doesn't take a char vector as a file or connection argument.
The following works but it seems like a lot of code:
> 
> data <- sub(" +","",data)   		# remove leading
blanks for strsplit
> data <- strsplit(data," +")   		# strsplit returns a list of
char vectors
> ndata <- character(0)			# vectorize the list of char vectors
> for (ii in 1:length(data)) ndata <- c(ndata,data[[ii]])  
> ndata <- as.numeric(ndata)				
> dim(ndata) <- c(3,length(data))	  	
> data <- t(ndata)
> data.frame(A=data[,1],B=data[,2],C=data[,3])
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595