Adding characters in all columns at once

Question

I have a three dataframes with 77 variables. They are all the same, they only differ in years (2014, 2015, 2016).

I want to merge them, but all the colnames are exactly the same, So I don't know which values belong to 2014, 2015 or 2015.

I want to solve this by adding the year to all colnames in the three dataframes.

So now I have:

df_2014:
a|b|c
1|2|3

df_2015
a|b|c|
4|5|6|

df_2016
a|b|c|
7|8|9|

I would like to have:

df_2014:
a(2014)|b(2014)|c(2014)
1|2|3

df_2015:
a(2015)|b(2015)|c(2015)|
4|5|6|

df_2016:
a(2016)|b(2016)|c(2016)|
7|8|9|

Does anyone know if I can do this with a loop or another function? Otherwise I need to rename the colnames 231 times ;)

thanks, Arnand

Answer 1

You could use setNames. For instance:

df_2017 <- data.frame(a = 1, b = 2, c = 3)

setNames(df_2017, paste("df_2017",colnames(df_2017), sep = "")) 

Output:
  df_2017a df_2017b df_2017c
1        1        2        3

Answer 2

have them all in a list first:

l = list(df2014, df2015, df2016)

lapply(seq_along(l), function(x) {colnames(l[[x]]) = paste0(colnames(l[[x]]) ,"(", x+2013, ")");l[[x]]})