Below is a script in bash the uses the awk tokenizer to do the work.
This assumes that your input and output delimiter is space. The number of
consecutive delimiters in
the input is not important. This also assumes that the input file does not have
a header row. That
is easy to modify if you want. I always keep header rows in my data files as I
think that removing
them is asking for trouble down the road.
I added a NULL for cases where there is no value for the last field. You could
use "." if you want.
You should be able to find how to run this from inside R if you want. You will,
of course, need a
bash environment to run this, so if you are not in linux you will need cygwin
or something similar.
This should be very fast, but let me know if needs to be faster. If the X1_X2
variant occurs less
frequently than not then we should switch the order in which the logic
evaluates the options.
LMH
#! /bin/bash
# input filename
input_file=$1
# output filename
output_file=$2
# make sure the input file exists
if [ ! -f $input_file ]; then
echo $input_file " cannot be found"
exit 0
fi
# create the output file
touch $output_file
# make sure the output was created
if [ ! -f $output_file ]; then
echo $output_file " was not created"
exit 0
fi
# write the header row
echo "ID1 ID2 Y1 X1 X2" >> $output_file
# character to find in the third token
look_for='_'
# process with awk
# if the 3rd token contains '_'
# split the third token on '_' into F[1] and F[2]
# print the first two tokens, the indicator value of 1, and the split fields
F[1] and F[2]
# otherwise,
# print the first two tokens, the indicator value of 0, the 3rd token, and
NULL
cat $input_file | \
awk -v find_char=$look_for '{ if($3 ~ find_char) { { split ($3, F, "_") }
{ print $1, $2, "1", F[1],
F[2] }
}
else { print $1, $2, "0", $3, "NULL" }
}' >> $output_file
Val wrote:
> Thank you all for the help!
>
> LMH, Yes I would like to see the alternative. I am using this for a
> large data set and if the alternative is more efficient than this
> then I would be happy.
>
> On Tue, Sep 22, 2020 at 6:25 PM Bert Gunter <bgunter.4...@gmail.com> wrote:
>>
>> To be clear, I think Rui's solution is perfectly fine and probably better
>> than what I offer below. But just for fun, I wanted to do it without the
>> lapply(). Here is one way. I think my comments suffice to explain.
>>
>>> ## which are the non "_" indices?
>>> wh <- grep("_",F1$text, fixed = TRUE, invert = TRUE)
>>> ## paste "_." to these
>>> F1[wh,"text"] <- paste(F1[wh,"text"],".",sep = "_")
>>> ## Now strsplit() and unlist() them to get a vector
>>> z <- unlist(strsplit(F1$text, "_"))
>>> ## now cbind() to the data frame
>>> F1 <- cbind(F1, matrix(z, ncol = 2, byrow = TRUE))
>>> F1
>> ID1 ID2 text 1 2
>> 1 A1 B1 NONE_. NONE .
>> 2 A1 B1 cf_12 cf 12
>> 3 A1 B1 NONE_. NONE .
>> 4 A2 B2 X2_25 X2 25
>> 5 A2 B3 fd_15 fd 15
>>> ## You can change the names of the 2 columns yourself
>>
>> Cheers,
>> Bert
>>
>> Bert Gunter
>>
>> "The trouble with having an open mind is that people keep coming along and
>> sticking things into it."
>> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>>
>>
>> On Tue, Sep 22, 2020 at 12:19 PM Rui Barradas <ruipbarra...@sapo.pt> wrote:
>>>
>>> Hello,
>>>
>>> A base R solution with strsplit, like in your code.
>>>
>>> F1$Y1 <- +grepl("_", F1$text)
>>>
>>> tmp <- strsplit(as.character(F1$text), "_")
>>> tmp <- lapply(tmp, function(x) if(length(x) == 1) c(x, ".") else x)
>>> tmp <- do.call(rbind, tmp)
>>> colnames(tmp) <- c("X1", "X2")
>>> F1 <- cbind(F1[-3], tmp) # remove the original column
>>> rm(tmp)
>>>
>>> F1
>>> # ID1 ID2 Y1 X1 X2
>>> #1 A1 B1 0 NONE .
>>> #2 A1 B1 1 cf 12
>>> #3 A1 B1 0 NONE .
>>> #4 A2 B2 1 X2 25
>>> #5 A2 B3 1 fd 15
>>>
>>>
>>> Note that cbind dispatches on F1, an object of class "data.frame".
>>> Therefore it's the method cbind.data.frame that is called and the result
>>> is also a df, though tmp is a "matrix".
>>>
>>>
>>> Hope this helps,
>>>
>>> Rui Barradas
>>>
>>>
>>> Às 20:07 de 22/09/20, Rui Barradas escreveu:
>>>> Hello,
>>>>
>>>> Something like this?
>>>>
>>>>
>>>> F1$Y1 <- +grepl("_", F1$text)
>>>> F1 <- F1[c(1, 2, 4, 3)]
>>>> F1 <- tidyr::separate(F1, text, into = c("X1", "X2"), sep = "_", fill =
>>>> "right")
>>>> F1
>>>>
>>>>
>>>> Hope this helps,
>>>>
>>>> Rui Barradas
>>>>
>>>> Às 19:55 de 22/09/20, Val escreveu:
>>>>> HI All,
>>>>>
>>>>> I am trying to create new columns based on another column string
>>>>> content. First I want to identify rows that contain a particular
>>>>> string. If it contains, I want to split the string and create two
>>>>> variables.
>>>>>
>>>>> Here is my sample of data.
>>>>> F1<-read.table(text="ID1 ID2 text
>>>>> A1 B1 NONE
>>>>> A1 B1 cf_12
>>>>> A1 B1 NONE
>>>>> A2 B2 X2_25
>>>>> A2 B3 fd_15 ",header=TRUE,stringsAsFactors=F)
>>>>> If the variable "text" contains this "_" I want to create an indicator
>>>>> variable as shown below
>>>>>
>>>>> F1$Y1 <- ifelse(grepl("_", F1$text),1,0)
>>>>>
>>>>>
>>>>> Then I want to split that string in to two, before "_" and after "_"
>>>>> and create two variables as shown below
>>>>> x1= strsplit(as.character(F1$text),'_',2)
>>>>>
>>>>> My problem is how to combine this with the original data frame. The
>>>>> desired output is shown below,
>>>>>
>>>>>
>>>>> ID1 ID2 Y1 X1 X2
>>>>> A1 B1 0 NONE .
>>>>> A1 B1 1 cf 12
>>>>> A1 B1 0 NONE .
>>>>> A2 B2 1 X2 25
>>>>> A2 B3 1 fd 15
>>>>>
>>>>> Any help?
>>>>> Thank you.
>>>>>
>>>>> ______________________________________________
>>>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>>>> 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.
>>>>>
>>>>
>>>> ______________________________________________
>>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>>> 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.
>>>
>>> ______________________________________________
>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> 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.
>
> ______________________________________________
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>
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