CODEWITHSUNDEEP
r
zerberus
zerberus

Reputation: 73

Create new sequential column if value in another column is non-unique

I have two columns x and y, I am trying to create a new sequenced column z if the value in one of the columns is non-unique. e.g.

x <- c("1", "1", "1", "1", "2", "2", "2", "3", "3", "3", "4", "4", "5", "6", "6", "6")
y <- c("Y", "Y", "Y", "Y", "N", "N", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "N", "Y", "Y")
df <- data.frame(x, y)

What I would like to get is the following:

#    x     y         z
#
#    1     Y         1
#    1     Y         2
#    1     Y         3
#    1     Y         4
#    2     N         1
#    2     N         2
#    2     Y         3
#    3     Y         1
#    3     Y         2
#    3     Y         3
#    4     Y         1
#    4     Y         2
#    5     Y         1
#    6     N         1
#    6     Y         2
#    6     Y         3

Upvotes: 0

Views: 117

Answers (1)

zerberus
zerberus

Reputation: 73

y <- c("Y", "Y", "Y", "Y", "N", "N", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "N", "Y", "Y")
df <- data.frame(x, y) 

df$z <- ave(df$x, df$x, FUN = seq_along)

gives

   x y z
1  1 Y 1
2  1 Y 2
3  1 Y 3
4  1 Y 4
5  2 N 1
6  2 N 2
7  2 Y 3
8  3 Y 1
9  3 Y 2
10 3 Y 3
11 4 Y 1
12 4 Y 2
13 5 Y 1
14 6 N 1
15 6 Y 2
16 6 Y 3

Upvotes: 1

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