[R] recode according to specific sequence of characters within a string variable

[Marc Schwartz]

Do you mean something like:

> with(DF.new, paste(person, year, paste("team", team, sep = ""), sep = "_"))
[1] "jeff_2001_teamx"   "jeff_2002_teamy"   "robert_2002_teamz"
[4] "mary_2002_teamz"   "mary_2003_teamy"  

?

See ?paste and ?with for more information, if so.

HTH,

Marc

On Feb 4, 2011, at 7:26 AM, Denis Kazakiewicz wrote:

> Dear R people
> Could you please help
> I have similar but opposite question
> How to reshape data from DF.new  to  DF from example, Mark kindly
> provided?
> 
> Thank you
> Denis
> 
> On Пят, 2011-02-04 at 07:09 -0600, Marc Schwartz wrote:
>> On Feb 4, 2011, at 6:32 AM, D. Alain wrote:
>> 
>>> Dear R-List, 
>>> 
>>> I have a dataframe with one column "name.of.report" containing character values, e.g.
>>> 
>>> 
>>>> df$name.of.report
>>> 
>>> "jeff_2001_teamx"
>>> "teamy_jeff_2002"
>>> "robert_2002_teamz"
>>> "mary_2002_teamz"
>>> "2003_mary_teamy"
>>> ...
>>> (i.e. the bit of interest is not always at same position)
>>> 
>>> Now I want to recode the column "name.of.report" into the variables "person", "year","team", like this
>>> 
>>>> new.df
>>> 
>>> "person"  "year"  "team"
>>> jeff           2001      x
>>> jeff           2002      y
>>> robert       2002      z
>>> mary        2002      z
>>> 
>>> I tried with grep()
>>> 
>>> df$person<-grep("jeff",df$name.of.report)
>>> 
>>> but of course it didn't exactly result in what I wanted to do. Could not find any solution via RSeek. Excuse me if it is a very silly question, but can anyone help me find a way out of this?
>>> 
>>> Thanks a lot
>>> 
>>> Alain
>> 
>> 
>> There will be several approaches, all largely involving the use of ?regex. Here is one:
>> 
>> 
>> DF <- data.frame(name.of.report = c("jeff_2001_teamx", "teamy_jeff_2002", 
>>                                    "robert_2002_teamz", "mary_2002_teamz", 
>>                                    "2003_mary_teamy"))
>> 
>>> DF
>>     name.of.report
>> 1   jeff_2001_teamx
>> 2   teamy_jeff_2002
>> 3 robert_2002_teamz
>> 4   mary_2002_teamz
>> 5   2003_mary_teamy
>> 
>> 
>> DF.new <- data.frame(person = gsub("[_0-9]|team.", "", DF$name.of.report),
>>                     year = gsub(".*([0-9]{4}).*","\\1", DF$name.of.report),
>>                     team = gsub(".*team(.).*","\\1", DF$name.of.report))
>> 
>> 
>>> DF.new
>>  person year team
>> 1   jeff 2001    x
>> 2   jeff 2002    y
>> 3 robert 2002    z
>> 4   mary 2002    z
>> 5   mary 2003    y
>> 
>> 
>> 
>> HTH,
>> 
>> Marc Schwartz