How to assign a custom unique id to different elements in a column?

Question

I have a column named quadrant in my dataset:

Quadrant
NW
NE
SW
NE

I want to create a new column named Quad_id containing custom ids for each direction like:

Quadrant      Quad_id
NW            10001 
NE            10002
SW            10003
NE            10002

Possible duplicate of [How to create a consecutive index based on a grouping variable in a dataframe](https://stackoverflow.com/questions/6112803/how-to-create-a-consecutive-index-based-on-a-grouping-variable-in-a-dataframe) — markus, Dec 02 '18 at 20:48

score 0 · Accepted Answer · answered Dec 02 '18 at 20:45

There are two possibilities:

You can use match:

transform(dat, id = match(Quadrant, Quadrant) + 10000)
#   Quadrant    id
# 1       NW 10001
# 2       NE 10002
# 3       SW 10003
# 4       NE 10002

where dat is the name of the data frame.

You can also use as.factor:

transform(dat, id = as.integer(as.factor(Quadrant)) + 10000)
#   Quadrant    id
# 1       NW 10002
# 2       NE 10001
# 3       SW 10003
# 4       NE 10001

How to assign a custom unique id to different elements in a column?

1 Answers1