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Hej,

This might have been reviewed before, plus my R skills are getting rusty, but I am trying to generate a new dataframe, where rownames will be generated from strings and effectif / sequence number from a two columns data frame.

To make more sense I have a dataframe looking like :

IND Effect
A 3
B 2
C 4

read.table(text = "IND Effect
A 3
B 2
C 4", h = T)

And I want something like

IND
A_1
A_2
A_3
B_1
B_2
C_1
C_2
C_3
C_4

on a new data frame. I tryed :

new = mapply(function(x, y) paste0(rep(x, y), collapse = "_"), IND , Effect)

but doesn't work as I would like....

aynber
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Ann Mo
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2 Answers2

1

You may nee the help of the seq_len() function:

df <- data.frame(ind = c("A", "B", "C"), 
                 effect = c(3, 2, 4))

paste(rep(df$ind, df$effect),
      unlist(sapply(df$effect, seq_len)), 
      sep = "_")
[1] "A_1" "A_2" "A_3" "B_1" "B_2" "C_1" "C_2" "C_3" "C_4"
abichat
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1

with mapply:

m <- mapply(paste, df$ind, sapply(df$effect, seq), sep = "_")

output

unlist(m)
#   A1    A2    A3    B1    B2    C1    C2    C3    C4 
#"A_1" "A_2" "A_3" "B_1" "B_2" "C_1" "C_2" "C_3" "C_4"

#or, as a data.frame object:
data.frame(new = unname(unlist(m)))
#  new
#1 A_1
#2 A_2
#3 A_3
#4 B_1
#5 B_2
#6 C_1
#7 C_2
#8 C_3
#9 C_4

data

df <- data.frame(ind = c("A", "B", "C"), 
                 effect = c(3, 2, 4))
Maël
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