CODEWITHSUNDEEP
rdataframe
YBC
YBC

Reputation: 39

Specified rows with same character in some rows in dataframe in R

I have a data frame with same character in specific rows:

a    1
a    3
a    7
b    4
b    8

I want to changed it:

a.1    1
a.2    3
a.3    7
b.1    4
b.2    8

Do you know any code in R for this?

Thanks a lot.

Upvotes: 0

Views: 62

Answers (3)

akrun
akrun

Reputation: 887108

We can use dplyr/tidyr. We group by 'V1', create a sequence column ('VN'), unite the columns 'V1' and 'VN', and then rename the column.

library(dplyr)
library(tidyr)
df %>%
   group_by(V1) %>%
   mutate(VN = row_number()) %>% 
   unite(V1n, V1, VN, sep='.') %>%
   rename(V1=V1n) 
#   V1    V2
#  (chr) (int)
#1   a.1     1
#2   a.2     3
#3   a.3     7
#4   b.1     4
#5   b.2     8

Upvotes: 0

Colonel Beauvel
Colonel Beauvel

Reputation: 31171

You can also use data.table package:

library(data.table)

setDT(df)[,ix:=paste(V1,1:.N, sep='.'),V1][]
#   V1 V2  ix
#1:  a  1 a.1
#2:  a  3 a.2
#3:  a  7 a.3
#4:  b  4 b.1
#5:  b  8 b.2

Data:

df = structure(list(V1 = structure(c(1L, 1L, 1L, 2L, 2L), .Label = c("a", 
"b"), class = "factor"), V2 = c(1L, 3L, 7L, 4L, 8L)), .Names = c("V1", 
"V2"), class = "data.frame", row.names = c(NA, -5L))

Upvotes: 2

talat
talat

Reputation: 70266

In base R, you could do:

df$V1 <- with(df, paste(V1, ave(as.numeric(V1), V1, FUN = seq_along), sep="."))
print(df)
#   V1 V2
#1 a.1  1
#2 a.2  3
#3 a.3  7
#4 b.1  4
#5 b.2  8

Upvotes: 1

Related Questions