Idiomatic Replacement for map/reduce/filter/etc
If you're still interested, the go-funk
package will enable you to do map/reduce/filter etc.
This library is at the time of answering regularly updated. The previous library mentioned hasn't been updated in 4 years.
Github - Go Funk
Simple apply/filter/reduce package.
I wanted to see how hard it was to implement this sort of thing in Go, with as nice an API as I could manage. It wasn't hard.
Having written it a couple of years ago, I haven't had occasion to use it once. Instead, I just use "for" loops.
You shouldn't use it either.
Rob Pike
Follow Rob's advice. Use for loops.