R question. Generate variables followed by number suffix in dataframe

Question

How do I generate a variables as below by just entering a number into a function (in this case 5)?

  rank  DATE  OP
1    1 DATE1 OP1
2    2 DATE2 OP2
3    3 DATE3 OP3
4    4 DATE4 OP4
5    5 DATE5 OP5
>

Which is the easiest way?

Clemsang · Answer 1 · 2020-01-15T08:40:56.507

1

You can use paste0:

create_df <- function(n){
  data.frame(rank = 1:n, DATE = paste0("DATE", 1:n), OP = paste0("OP", 1:n))
}
create_df(5)

edited Jan 15 '20 at 08:40

answered Jan 15 '20 at 08:37

Clemsang

clean solution. For DATE and OP, the `1:5` should be a `1:n` though. – NicolasH2 Jan 15 '20 at 08:40
Thanks. How do I then create the dataframe in the global env inside the function? – hklovs Jan 15 '20 at 13:12
Just store it `df <- create_df(5)` – Clemsang Jan 15 '20 at 13:14
Ah of course. Thanks again ;) – hklovs Jan 15 '20 at 13:21

score 0 · Answer 2 · answered Jan 15 '20 at 08:36

Here is a base R solution using paste0:

df <- cbind(df[1],sapply(names(df)[-1], paste0, 1:nrow(df)))

such that

> df
  rank  DATE  OP
1    1 DATE1 OP1
2    2 DATE2 OP2
3    3 DATE3 OP3
4    4 DATE4 OP4
5    5 DATE5 OP5

DATA

df <- structure(list(rank = 1:5, DATE = c(NA, NA, NA, NA, NA), OP = c(NA, 
NA, NA, NA, NA)), class = "data.frame", row.names = c(NA, -5L
))

2 Answers2