CODEWITHSUNDEEP
r
mreze
mreze

Reputation: 5

Creating a group variable

I have this dataframe df:

    A       B
    value1  a
    value1  b
    value1  c
    value2  a
    value2  b
   value 2  c
   value 2  d

And I'd like to have something like this

A       B  group
value1  a  1
value1  b  1
value1  c  1
value2  a  2
value2  b  2
value2  c  2
value2  d  2

That is, I'd like to create a variable that groups the same A values. How would you say it is the best way to do this?

Example

    id          code  
    2012-10-20  R     
    2012-10-20  L     
    2012-10-20  K     
    2015-04-28  K     
    2015-04-28  L     
    2015-04-28  L

Desidered:

    id          code  group
    2012-10-20  R     1
    2012-10-20  L     1
    2012-10-20  K     1
    2015-04-28  K     2
    2015-04-28  L     2
    2015-04-28  L     2

Thank you!

Upvotes: 0

Views: 70

Answers (2)

gwatson
gwatson

Reputation: 488

If you just want to use the values in A as a group, then you already have that. If you want to create an ordered grouping from A and A is an ordered variable (date, numeric, factor, etc) then do something like:

library(dplyr)

df %>% mutate(group = dense_rank(A))

Upvotes: 0

C_Z_
C_Z_

Reputation: 7816

Probably the simplest way to do this is with as.factor

df$group <- as.numeric(as.factor(df$id))

Upvotes: 2

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