instead of doing:
df_combine = data.frame()
for (file in files){
df_curr = read.csv(file)
df_combine = rbind(df_combine, df_curr)do
library(data.table)
df_list = list()
for (file in files){
df_list[file] = read.csv(file)
df_combine = rbindlist(df_list)it's much faster!!