R help - Jul 2008 - Re ad in a file - produce independent vectors

Is there a way of reading in a file in a way that each line becomes a vector:
for example:

meals.txt

breakfast    bacon    eggs    sausage
lunch    sandwich    apple    marsbar    crisps
dinner    chicken    rice    custard    pie

I want to read in this file and end up with 3 different vectors, one called
breakfast which contains "bacon", "eggs", sausage" One
called lunch with
"sandwich", "apple"... etc

So is there a way to do this with a file like this?

Or would I need to transpose the file using something like Perl? And since
the vectors are not all of equal length, would I have to also increase the
size of the shorter lines by adding NAs? I'm working with a file much bigger
than this and this could be a bit of a bother...

Kind Regards,

Jim
-- 
View this message in context:
http://www.nabble.com/Read-in-a-file---produce-independent-vectors-tp18280318p18280318.html
Sent from the R help mailing list archive at Nabble.com.

Just read them in as whole lines and then split them
giving a list of vectors.  See ?readLines and ?strsplit

Lines <- readLines("meat.txt")
strsplit(Lines, " +")

This can also be done using strapply in gsubfn which
extracts words rather than splitting on delimiters:

library(gsubfn)
strapply(Lines, "\\w+")

More info on gsubfn is at http://gsubfn.googlecode.com


On Fri, Jul 4, 2008 at 10:38 AM, jimineep <jamesrperkins at hotmail.com>
wrote:
>
> Is there a way of reading in a file in a way that each line becomes a
vector:
> for example:
>
> meals.txt
>
> breakfast    bacon    eggs    sausage
> lunch    sandwich    apple    marsbar    crisps
> dinner    chicken    rice    custard    pie
>
> I want to read in this file and end up with 3 different vectors, one called
> breakfast which contains "bacon", "eggs", sausage"
One called lunch with
> "sandwich", "apple"... etc
>
> So is there a way to do this with a file like this?
>
> Or would I need to transpose the file using something like Perl? And since
> the vectors are not all of equal length, would I have to also increase the
> size of the shorter lines by adding NAs? I'm working with a file much
bigger
> than this and this could be a bit of a bother...
>
> Kind Regards,
>
> Jim
> --
> View this message in context:
http://www.nabble.com/Read-in-a-file---produce-independent-vectors-tp18280318p18280318.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

Hi

r-help-bounces at r-project.org napsal dne 04.07.2008 16:38:08:
> 
> Is there a way of reading in a file in a way that each line becomes a 
vector:
> for example:
> 
> meals.txt
> 
> breakfast    bacon    eggs    sausage
> lunch    sandwich    apple    marsbar    crisps
> dinner    chicken    rice    custard    pie
> 
> I want to read in this file and end up with 3 different vectors, one 
called
> breakfast which contains "bacon", "eggs", sausage"
One called lunch with
> "sandwich", "apple"... etc
You can read it through

read.table("meals.txt", sep="", header=F, fill=T, as.is=T)

see ?read.table for info about parameters.

You will get data frame and then you can manipulate it easily. It depends 
what do you want to do next with your food.

Regards
Petr
> 
> So is there a way to do this with a file like this?
> 
> Or would I need to transpose the file using something like Perl? And 
since
> the vectors are not all of equal length, would I have to also increase 
the
> size of the shorter lines by adding NAs? I'm working with a file much 
bigger
> than this and this could be a bit of a bother...
> 
> Kind Regards,
> 
> Jim
> -- 
> View this message in context: 
http://www.nabble.com/Read-in-a-file---produce-
> independent-vectors-tp18280318p18280318.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

on 07/04/2008 09:38 AM jimineep wrote:
> Is there a way of reading in a file in a way that each line becomes a
vector:
> for example:
> 
> meals.txt
> 
> breakfast    bacon    eggs    sausage
> lunch    sandwich    apple    marsbar    crisps
> dinner    chicken    rice    custard    pie
> 
> I want to read in this file and end up with 3 different vectors, one called
> breakfast which contains "bacon", "eggs", sausage"
One called lunch with
> "sandwich", "apple"... etc
> 
> So is there a way to do this with a file like this?
> 
> Or would I need to transpose the file using something like Perl? And since
> the vectors are not all of equal length, would I have to also increase the
> size of the shorter lines by adding NAs? I'm working with a file much
bigger
> than this and this could be a bit of a bother...
> 
> Kind Regards,
> 
> Jim
First, read in the data file using:

Lines <- readLines("meals.txt")

That gives you:

 > Lines
[1] "breakfast    bacon    eggs    sausage"
[2] "lunch    sandwich    apple    marsbar    crisps"
[3] "dinner    chicken    rice    custard    pie"


Note the current object list:

 > ls()
[1] "DF"    "Lines"


# Now loop over each line, split it
# then take the first value and use assign()
# to create a vector with that name, containing
# the remaining elements

for (i in seq(along = Lines)) {
   Vec <- unlist(strsplit(Lines[i], " +"))
   assign(Vec[1], Vec[-1])
}


Note the current object list:

 > ls()
[1] "breakfast" "DF"        "dinner"   
"i"         "Lines"
[6] "lunch"     "Vec"


 > breakfast
[1] "bacon"   "eggs"    "sausage"

 > lunch
[1] "sandwich" "apple"    "marsbar" 
"crisps"

 > dinner
[1] "chicken" "rice"    "custard" "pie"



HTH,

Marc Schwartz

On Fri, 4 Jul 2008, jimineep wrote:
>
> Is there a way of reading in a file in a way that each line becomes a
vector:
> for example:
>
> meals.txt
>
> breakfast    bacon    eggs    sausage
> lunch    sandwich    apple    marsbar    crisps
> dinner    chicken    rice    custard    pie
>
> I want to read in this file and end up with 3 different vectors, one called
> breakfast which contains "bacon", "eggs", sausage"
One called lunch with
> "sandwich", "apple"... etc
>
> So is there a way to do this with a file like this?
There are very many ways.

Perhaps one of the simplest is to use readLines() to get a character 
vector of one element per line, then strsplit() to split the line on 
whatever the separator used is. E.g.

meals <- readLines("meals.txt")
m2 <- strsplit(meals, " +")
names(m2) <- sapply(m2, `[`, 1)
m3 <- lapply(m2, `[`, -1)
> m3
$breakfast
[1] "bacon"   "eggs"    "sausage"

$lunch
[1] "sandwich" "apple"    "marsbar" 
"crisps"

$dinner
[1] "chicken" "rice"    "custard" "pie"


-- 
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