I am trying to write a loop in R but I think the nomenclature is not correct as it does not create the new objects, here is a simplified example of what I am trying to do: for i in (1:8) { List_i <-List colsToGrab_i <-grep(predefinedRegex_i, colnames(List_i$table)) List_i$table <- List_i$table[,predefinedRegex_i] } I have created 'predefinedRegex'es 1:8 which the grep should use to search The loop creates an object called "List_i" and then fails to find "predefinedRegex_i". I have tried putting quotes around the "i" and $ in front of the i but these do not work. Any help much appreciated. Thank you.