Streams

Post Example
Examples Filter
Stdin Line Filter in Go
by yhuang Go bufio bufio.NewScanner fmt fmt.Fprintln fmt.Println
Here’s an example line filter in Go that writes a capitalized version of all input text. You can use this pattern to write your own Go line filters.
package main

import (
    "bufio"
    "fmt"
    "os"
    "strings"
)

func main() {

    // Wrapping the unbuffered os.Stdin with a buffered scanner gives us a convenient
    // Scan method that advances the scanner to the next token;
    // which is the next line in the default scanner.
    scanner := bufio.NewScanner(os.Stdin)

    for scanner.Scan() {

        ucl := strings.ToUpper(scanner.Text())
        // Write out the uppercased line.
        fmt.Println(ucl)
    }

    if err := scanner.Err(); err != nil {
        fmt.Fprintln(os.Stderr, "error:", err)
        os.Exit(1)
    }
}
Write to Stdout in V
by yhuang V 
// println is a simple yet powerful builtin function.
// It can print anything: strings, numbers, arrays, maps, structs.
println(1) // "1"
println('hi') // "hi"
println([1,2,3]) // "[1, 2, 3]"

// Printing structs coming soon
println(User{name:'Bob', age:20}) // "User{name:'Bob', age:20}"
// If you want to define a custom print value for your type, simply define a .str() string method.
// If you don't want to print a newline, use print() instead.
Write to Stderr in V
by yhuang V 
eprintln("hello error")