Columnize

Easy column-formatted output for golang

Note: this fork of https://github.com/ryanuber/columnize adds a cheap implementation to work with coloured text using some ANSII excape codes

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/giantswarm/columnize"
)

func main() {
    output := []string{
        "Name | Gender | Age",
        "Bob | Male | 38",
        "Sally | Female | 9",
    }
    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  9

To right-align a column, edit a config's ColumnSpec and use columnize.Format instead of columnize.SimpleFormat. Example:

    config := columnize.DefaultConfig()
    config.ColumnSpec = []*columnize.ColumnSpecification{
        &columnize.ColumnSpecification{Alignment: columnize.AlignLeft},
        &columnize.ColumnSpecification{Alignment: columnize.AlignLeft},
        &columnize.ColumnSpecification{Alignment: columnize.AlignRight},
    }
    result := columnize.Format(output, config)

The result:

Name   Gender  Age
Bob    Male     38
Sally  Female    9

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