columnize

README

Columnize

Easy column-formatted output for golang

Columnize is a really small Go package that makes building CLI's a little bit easier. In some CLI designs, you want to output a number similar items in a human-readable way with nicely aligned columns. However, figuring out how wide to make each column is a boring problem to solve and eats your valuable time.

Here is an example:

package main

import (
    "fmt"
    "github.com/ryanuber/columnize"
)

func main() {
    output := []string{
        "Name | Gender | Age",
        "Bob | Male | 38",
        "Sally | Female | 26",
    }
    result := columnize.SimpleFormat(output)
    fmt.Println(result)
}

As you can see, you just pass in a list of strings. And the result:

Name   Gender  Age
Bob    Male    38
Sally  Female  26

Columnize is tolerant of missing or empty fields, or even empty lines, so passing in extra lines for spacing should show up as you would expect.

Configuration

Columnize is configured using a Config, which can be obtained by calling the DefaultConfig() method. You can then tweak the settings in the resulting Config:

config := columnize.DefaultConfig()
config.Delim = "|"
config.Glue = "  "
config.Prefix = ""
config.Empty = ""

• Delim is the string by which columns of input are delimited
• Glue is the string by which columns of output are delimited
• Prefix is a string by which each line of output is prefixed
• Empty is a string used to replace blank values found in output

You can then pass the Config in using the Format method (signature below) to have text formatted to your liking.

Usage

SimpleFormat(intput []string) string

Format(input []string, config *Config) string

Documentation

Index

• func Format(lines []string, config *Config) string
• func SimpleFormat(lines []string) string
• type Config
  • func DefaultConfig() *Config
  • func MergeConfig(a, b *Config) *Config

Functions

func Format

func Format(lines []string, config *Config) string

Format is the public-facing interface that takes either a plain string or a list of strings and returns nicely aligned output.

func SimpleFormat

func SimpleFormat(lines []string) string

Convenience function for using Columnize as easy as possible.

Types

type Config

type Config struct {
	// The string by which the lines of input will be split.
	Delim string

	// The string by which columns of output will be separated.
	Glue string

	// The string by which columns of output will be prefixed.
	Prefix string

	// A replacement string to replace empty fields
	Empty string
}

func DefaultConfig

func DefaultConfig() *Config

Returns a Config with default values.

func MergeConfig

func MergeConfig(a, b *Config) *Config

MergeConfig merges two config objects together and returns the resulting configuration. Values from the right take precedence over the left side.