.net - What is the fastest method to merge a number of files into a file in c#? -

i handle big files(of capacities minimum 500mb) split , merge c#.

i have split file thousands of files, sort these files groups, , merge these each group.

the minimum number of files 10,000.

i implement merge function using method stream.copyto(). here main part of that.

using (stream writer = file.openwrite(outputfilepath)) {       int filenum = filepaths.count();       (int = 0; < filenum; i++)       {            using (stream reader = file.openread(filepaths.elementat(i)))            { reader.copyto(writer); }        } } 

i've tested program split 500mb 17000 files of 2 groups , merge each group of 8500 files 1 file.

the merging part takes 80 seconds. think pretty slow compared splitting same file takes 15~20 seconds

is there method faster code?

your code looks fine elementat code smell. convert array , use [i] instead. if have 10k elements i'm positive you're wasting lot of time.