I have a df:
df1 <- data.frame(ID = c('a', 'b', 'c', 'c1', 'd', 'e', 'f', 'g', 'h', 'h1'),
var2 = c(7, 9, 2, 4, 3, 6, 8, 2, 1, 2),
var3 = c(21, 50, 40, 30, 29, 45, 33, 51, 70, 46),
var4 = c(1, 5, 2, 4, 1, 2, 3, 3, 5, 1))
Which I want to convert from wide to long format. I need to do this repeatedly for a number of different dataframes with different column names and numbers. The columns to convert will always be between the second and last column, using something like this:
data_long <- gather(df1, ID, num, df1[c(2:ncol(df1))], factor_key=TRUE)
So that the output looks like the following:
> data_long
ID num
1 var2 7
2 var2 9
3 var2 2
4 var2 4
5 var2 3
6 var2 6
7 var2 8
8 var2 2
9 var2 1
10 var2 2
11 var3 21
12 var3 50
13 var3 40
14 var3 30
15 var3 29
16 var3 45
17 var3 33
18 var3 51
19 var3 70
20 var3 46
21 var4 1
22 var4 5
23 var4 2
24 var4 4
25 var4 1
26 var4 2
27 var4 3
28 var4 3
29 var4 5
30 var4 1
Is it what you want?
tidyr::pivot_longer(df1, -ID)
# A tibble: 30 × 3
ID name value
<chr> <chr> <dbl>
1 a var2 7
2 a var3 21
3 a var4 1
4 b var2 9
5 b var3 50
6 b var4 5
7 c var2 2
8 c var3 40
9 c var4 2
10 c1 var2 4
# ℹ 20 more rows
# ℹ Use `print(n = ...)` to see more rows
Or even pivot_longer(df1, -1) if ID column name is also subject to change