[R] How to replace the values in a column

[andrija djurovic]

Hi.

You can do something like this:

df <- read.table(textConnection("
Gen    Rep
A_1      1
A_1       2
A_2     1
A_2     2
B_1       1
B_1       2
B_3       1
B_3       2
OP1_1   1
OP1_1   2
OP1_5   1
OP1_5   2"),header=TRUE,stringsAsFactors=FALSE)

str(df)

#adding a new column
cbind(df,ncol =
ifelse(df$Gen=="A_1","Wynda",ifelse(df$Gen=="B_3","Wynda",df$Gen)))

#replacing exisiting values
df$Gen[df$Gen=="A_1" | df$Gen=="B_3"] <- "Wynda"
df


Andrija




On Wed, Feb 29, 2012 at 7:06 AM, ilai <keren at math.montana.edu> wrote:
> Hannah,
> If Gen is a factor you can simply build the new factor "on top" of it:
>
> dataframe$Gen<- factor( c('Wynda' , 'A_2' , 'B_1' , 'Wynda' , 'Wynda'
> , 'OP1_5')[Gen] )
>
> Just make sure the replacement labels are in the same order as levels(Gen).
>
> Cheers
>
> On Tue, Feb 28, 2012 at 8:39 PM, hannahmaohuang
> <hannahmaohuang at gmail.com> wrote:
>> Dear All,
>> I've been searching relevant topics about replacing values, none seemed to
>> be applicable to me...
>>
>> I have a file with many many varieties, and want to replace some of them
>> into different names.
>> I tried various of ways, still don't know how to do that most efficiently..
>> Here is part of the example data:
>>
>>
>> Gen    Rep
>> A_1      1
>> A_1       2
>> A_2     1
>> A_2     2
>> B_1       1
>> B_1       2
>> B_3       1
>> B_3       2
>> OP1_1   1
>> OP1_1   2
>> OP1_5   1
>> OP1_5   2
>>
>> For example, I want to replace  A_1,  B_3,  OP1_1 into different name
>> "Wynda"
>>
>> So that the expected file should become:
>>
>> Gen          Rep
>> Wynda      1
>> Wynda        2
>> A_2           1
>> A_2           2
>> B_1              1
>> B_1             2
>> Wynda        1
>> Wynda        2
>> Wynda        1
>> Wynda        2
>> OP1_5          1
>> OP1_5         2
>>
>>
>> I have created a link file, which contains two rows, translating which Gen
>> correlating to which Name. Not sure if this file helps or not, example as
>> below:
>>
>> Column1(Gen)        Column2(Name)
>> A_1                               Wynda
>> A_2                                 A_2
>> B_1                                 B_1
>> B_3                             Wynda
>> OP1_1                       Wynda
>> OP1_5                        OP1_5
>>
>>
>> Though I can replace one by one in excel, since there are too many files and
>> too many reps, it'll be very time-consuming also easy to make mistakes.
>>
>> Please give me any guidance or help in terms of finish this with R.
>>
>> Thanks so much !
>>
>> Sincerely
>> Hannah
>>
>>
>>
>> --
>> View this message in context: http://r.789695.n4.nabble.com/How-to-replace-the-values-in-a-column-tp4430448p4430448.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.
>
> ______________________________________________
> 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.