Reads text from stdin, outputs CSV-formatted list of every unicode character (rune) in the file together with a number that says how much it appears

charcount.go

package main

// Because this code is so short and obvious, it should be considered public domain

import "os"
import "io/ioutil"
import "encoding/csv"
import "strconv"

func main() {
        input, err := ioutil.ReadAll(os.Stdin)
        if err != nil {
                panic(err)
        }
        inputs := string(input)
        output := map[rune]int{}
        for _, c := range inputs {
                output[c]++
        }
        outputc := csv.NewWriter(os.Stdout)
        for k, v := range output {
                outputc.Write([]string{string(k), strconv.Itoa(v)})
        }
        outputc.Flush()
        if outputc.Error() != nil {
                panic(outputc.Error())
        }
}