【Go】用Go在命令行输出好看的表格

前言

最近在写一些运维小工具，比如批量进行ping包的工具，实现不困难，反正就是ping，统计，然后输出，不过我本着自己既是开发者又是使用者的理念，还是不喜欢输出特别难看的工具，就像这样：

所以就去https://pkg.go.dev/瞄了一眼，看看有没有啥适合的库能够把输出整的好看点的，于是找到了一个库github.com/jedib0t/go-pretty/v6/table，这是一个在命令行输出格式化表格的库，这里记录一下使用这个库进行一些格式化输出的过程。

其实还有一个比较简单的库叫做gotable，也能实现基础的格式化输出功能，使用起来也方便些，不过功能相对来说就要单一一些，在表格样式设置上会差一些，没那么自由，也可以看下https://pkg.go.dev/github.com/liushuochen/gotable#section-readme

正文

接下来开始正式的去在命令行生成好看的满足需要的表格。

生成Table

首先我们要生成一个Table结构体的实例，可以直接New一个，也可以自己构造：

t := table.Table{}
// 或者
t := table.NewWriter()

NewWriter会返回一个Writer接口

表头设置

表格首先要设置表头，以我的应用为例，表头设置：

header := table.Row{"ID", "IP", "Num", "PacketsRecv", "PacketLoss", "AvgRtt"}

这样生成了一个表头行，然后要通过AppendHeader方法在表格中生效：

t.AppendHeader(header)

看看效果，表头已经打印出来了

+----+----+-----+-------------+------------+--------+
| ID | IP | NUM | PACKETSRECV | PACKETLOSS | AVGRTT |
+----+----+-----+-------------+------------+--------+
+----+----+-----+-------------+------------+--------+

插入行

数据的插入和表头的生成类似，要生成一个table.Row，然后调用AppendRow方法：

func (d *Demo) AppendRow() {for i := 1; i <= 5; i++ {row := table.Row{i, fmt.Sprintf("10.0.0.%v", i), i + 4, i, i, "AppendRow"}d.T.AppendRow(row)}
}

效果如下：

+----+----------+-----+-------------+------------+-----------+
| ID | IP       | NUM | PACKETSRECV | PACKETLOSS | AVGRTT    |
+----+----------+-----+-------------+------------+-----------+
|  1 | 10.0.0.1 |   5 |           1 |          1 | AppendRow |
|  2 | 10.0.0.2 |   6 |           2 |          2 | AppendRow |
|  3 | 10.0.0.3 |   7 |           3 |          3 | AppendRow |
|  4 | 10.0.0.4 |   8 |           4 |          4 | AppendRow |
|  5 | 10.0.0.5 |   9 |           5 |          5 | AppendRow |
+----+----------+-----+-------------+------------+-----------+

当然也可以生成table.Row的切片后调用一次AppendRows方法，效果和上面是一样的：

func (d *Demo) AppendRows() {var rows []table.Rowfor i := 1; i <= 5; i++ {rows = append(rows, table.Row{i, fmt.Sprintf("10.0.0.%v", i), i + 4, i, i, "AppendRows"})}d.T.AppendRows(rows)
}

+----+----------+-----+-------------+------------+------------+
| ID | IP       | NUM | PACKETSRECV | PACKETLOSS | AVGRTT     |
+----+----------+-----+-------------+------------+------------+
|  1 | 10.0.0.1 |   5 |           1 |          1 | AppendRow  |
|  2 | 10.0.0.2 |   6 |           2 |          2 | AppendRow  |
|  3 | 10.0.0.3 |   7 |           3 |          3 | AppendRow  |
|  4 | 10.0.0.4 |   8 |           4 |          4 | AppendRow  |
|  5 | 10.0.0.5 |   9 |           5 |          5 | AppendRow  |
|  1 | 10.0.0.1 |   5 |           1 |          1 | AppendRows |
|  2 | 10.0.0.2 |   6 |           2 |          2 | AppendRows |
|  3 | 10.0.0.3 |   7 |           3 |          3 | AppendRows |
|  4 | 10.0.0.4 |   8 |           4 |          4 | AppendRows |
|  5 | 10.0.0.5 |   9 |           5 |          5 | AppendRows |
+----+----------+-----+-------------+------------+------------+

表格标题

在设置表格实际内容时，还可以设置一个表格标题，如下：

func (d *Demo) AddTitle() {d.T.SetTitle("This is Easy Table")
}

+-------------------------------------------------------------+
| This is Easy Table                                          |
+----+----------+-----+-------------+------------+------------+
| ID | IP       | NUM | PACKETSRECV | PACKETLOSS | AVGRTT     |
+----+----------+-----+-------------+------------+------------+
|  1 | 10.0.0.1 |   5 |           1 |          1 | AppendRow  |
|  2 | 10.0.0.2 |   6 |           2 |          2 | AppendRow  |
|  1 | 10.0.0.1 |   5 |           1 |          1 | AppendRows |
|  2 | 10.0.0.2 |   6 |           2 |          2 | AppendRows |
+----+----------+-----+-------------+------------+------------+

自动标号

在插入行的时候，我额外输入了一个ID列，作为标号，其实table提供了相关的方法和接口，只需要调用SetAutoIndex方法，增加自动的索引列即可：

func (d *Demo) MakeHeader() {header := table.Row{"IP", "Num", "PacketsRecv", "PacketLoss", "AvgRtt"}d.T.AppendHeader(header)d.T.SetAutoIndex(true)
}

+------------------------------------------------------------+
| This is Easy Table                                         |
+---+----------+-----+-------------+------------+------------+
|   | IP       | NUM | PACKETSRECV | PACKETLOSS | AVGRTT     |
+---+----------+-----+-------------+------------+------------+
| 1 | 10.0.0.1 |   5 |           1 |          1 | AppendRow  |
| 2 | 10.0.0.2 |   6 |           2 |          2 | AppendRow  |
| 3 | 10.0.0.1 |   5 |           1 |          1 | AppendRows |
| 4 | 10.0.0.2 |   6 |           2 |          2 | AppendRows |
+---+----------+-----+-------------+------------+------------+

单元格合并

有的时候，相邻单元格的值一样我们可能会想要进行合并，这样更美观，单元格合并分为列合并和行合并；先定义一下这里的列合并和行合并：

• 列合并：针对单列，如果单列中的多个相邻行数据一样，那么就合并为一个大行；
• 行合并：针对单行，如果单行中的多个相邻列数据一样，那么久合并为一个大列；

这里我们用到的原始表格如下：

+--------------------------------------------------------------+
| This is Easy Table                                           |
+---+----------+-------+-------------+------------+------------+
|   | IP       |   NUM | PACKETSRECV | PACKETLOSS | AVGRTT     |
+---+----------+-------+-------------+------------+------------+
| 1 | 10.0.0.1 |     5 |           1 |          1 | AppendRow  |
| 2 | 10.0.0.2 |     6 |           2 |          2 | AppendRow  |
| 3 | 10.0.0.1 |     5 |           1 |          1 | AppendRows |
| 4 | 10.0.0.2 |     6 |           2 |          2 | AppendRows |
+---+----------+-------+-------------+------------+------------+
|   | TOTAL    | TOTAL |       TOTAL |      TOTAL | 4          |
+---+----------+-------+-------------+------------+------------+

列合并

我们先进行最后一列AvgRtt的列合并：

func (d *Demo) ColumnMerge() {d.T.SetColumnConfigs([]table.ColumnConfig{{Name: "AvgRtt",// Number是指定列的序号// Number: 5,AutoMerge: true,Align:     text.AlignCenter,},})
}

可以选择通过列的表头或者列的序号来选择具体进行合并的列：

+---+----------+-------+-------------+------------+------------+
|   | IP       |   NUM | PACKETSRECV | PACKETLOSS | AVGRTT     |
+---+----------+-------+-------------+------------+------------+
| 1 | 10.0.0.1 |     5 |           1 |          1 |  AppendRow |
| 2 | 10.0.0.2 |     6 |           2 |          2 |            |
| 3 | 10.0.0.1 |     5 |           1 |          1 | AppendRows |
| 4 | 10.0.0.2 |     6 |           2 |          2 |            |
+---+----------+-------+-------------+------------+------------+
|   | TOTAL    | TOTAL |       TOTAL |      TOTAL | 4          |
+---+----------+-------+-------------+------------+------------+

这样看表格线条不明显，感觉不到区分，那么可以加上一些设置d.T.Style().Options.SeparateRows = true

+---+----------+-------+-------------+------------+------------+
|   | IP       |   NUM | PACKETSRECV | PACKETLOSS | AVGRTT     |
+---+----------+-------+-------------+------------+------------+
| 1 | 10.0.0.1 |     5 |           1 |          1 |  AppendRow |
+---+----------+-------+-------------+------------+            |
| 2 | 10.0.0.2 |     6 |           2 |          2 |            |
+---+----------+-------+-------------+------------+------------+
| 3 | 10.0.0.1 |     5 |           1 |          1 | AppendRows |
+---+----------+-------+-------------+------------+            |
| 4 | 10.0.0.2 |     6 |           2 |          2 |            |
+---+----------+-------+-------------+------------+------------+
|   | TOTAL    | TOTAL |       TOTAL |      TOTAL | 4          |
+---+----------+-------+-------------+------------+------------+

行合并

行合并我们对最后一行的汇总行进行合并，具体做法是在添加汇总行时增加RowConfig参数：

func (d *Demo) AppendFooter() {d.T.AppendFooter(table.Row{"Total", "Total", "Total", "Total", count}, table.RowConfig{AutoMerge: true})
}

+---+----------+-------+-------------+------------+------------+
|   | IP       |   NUM | PACKETSRECV | PACKETLOSS | AVGRTT     |
+---+----------+-------+-------------+------------+------------+
| 1 | 10.0.0.1 |     5 |           1 |          1 |  AppendRow |
+---+----------+-------+-------------+------------+            |
| 2 | 10.0.0.2 |     6 |           2 |          2 |            |
+---+----------+-------+-------------+------------+------------+
| 3 | 10.0.0.1 |     5 |           1 |          1 | AppendRows |
+---+----------+-------+-------------+------------+            |
| 4 | 10.0.0.2 |     6 |           2 |          2 |            |
+---+----------+-------+-------------+------------+------------+
|   |                    TOTAL                    | 4          |
+---+---------------------------------------------+------------+

样式设置

现在整个表格已经生成，但我们还需要进行一些美化，这就要对表格的样式进行设置了；

居中设置

对于居中，无法直接进行全局的设置，必须根据列进行，如下：

func (d *Demo) SetAlignCenter() {column := []string{"IP", "Num", "PacketsRecv", "PacketLoss", "AvgRtt"}c := []table.ColumnConfig{}// 根据表格的列数循环进行设置，统一居中for i := 1; i <= len(column); i++ {name := column[i-1]if name == "AvgRtt" {c = append(c, table.ColumnConfig{Name:        "AvgRtt",AutoMerge:   true,Align:       text.AlignCenter,AlignHeader: text.AlignCenter,AlignFooter: text.AlignCenter,})continue}c = append(c, table.ColumnConfig{Name:        column[i],Align:       text.AlignCenter,AlignHeader: text.AlignCenter,AlignFooter: text.AlignCenter,})}d.T.SetColumnConfigs(c)
}

居中效果如下，这样既能保留列合并又完成了剧中设置：

+---+----------+-------+-------------+------------+------------+
|   | IP       |  NUM  | PACKETSRECV | PACKETLOSS |   AVGRTT   |
+---+----------+-------+-------------+------------+------------+
| 1 | 10.0.0.1 |   5   |      1      |      1     |  AppendRow |
+---+----------+-------+-------------+------------+            |
| 2 | 10.0.0.2 |   6   |      2      |      2     |            |
+---+----------+-------+-------------+------------+------------+
| 3 | 10.0.0.1 |   5   |      1      |      1     | AppendRows |
+---+----------+-------+-------------+------------+            |
| 4 | 10.0.0.2 |   6   |      2      |      2     |            |
+---+----------+-------+-------------+------------+------------+
|   |                    TOTAL                    |      4     |
+---+---------------------------------------------+------------+

数字自动高亮标红

在我的应用场景中，ping的ip如果出现了丢包情况，那就要红色高亮，方便使用者马上关注到，这种情况下，可以通过Transformer来设置：

func (d *Demo) SetWarnColor() {// 字体颜色WarnColor := text.Colors{text.BgRed}warnTransformer := text.Transformer(func(val interface{}) string {if val.(float64) > 0 {// 统计丢包服务器总数return WarnColor.Sprintf("%.2f%%", val)}return fmt.Sprintf("%v%%", val)})d.T.SetColumnConfigs([]table.ColumnConfig{{Name:        "PacketLoss",AutoMerge:   true,Align:       text.AlignCenter,AlignHeader: text.AlignCenter,AlignFooter: text.AlignCenter,Transformer: warnTransformer,},})
}

实际效果如下：

完整Demo代码

package mainimport ("fmt""math/rand""github.com/jedib0t/go-pretty/v6/table""github.com/jedib0t/go-pretty/v6/text"
)var count = 0type Demo struct {T table.Writer
}func NewDemo() *Demo {return &Demo{T: table.NewWriter(),}
}func (d *Demo) MakeHeader() {header := table.Row{"IP", "Num", "PacketsRecv", "PacketLoss", "AvgRtt"}d.T.AppendHeader(header)d.T.SetAutoIndex(true)// d.T.SetStyle(table.StyleLight)d.T.Style().Options.SeparateRows = true
}func (d *Demo) AddTitle() {d.T.SetTitle("This is Easy Table")
}func (d *Demo) AppendRow() {// rowConfig := table.RowConfig{AutoMerge: true}for i := 1; i <= 2; i++ {row := table.Row{fmt.Sprintf("10.0.0.%v", i), i + 4, i, rand.Float64() * 100, "AppendRow"}count += 1d.T.AppendRow(row)}d.T.AppendRow(table.Row{fmt.Sprintf("10.0.0.%v", 4), 1 + 4, 1, 0.0, "AppendRow"})
}func (d *Demo) AppendRows() {var rows []table.Rowfor i := 1; i <= 2; i++ {rows = append(rows, table.Row{fmt.Sprintf("10.0.0.%v", i), i + 4, i, rand.Float64() * 100, "AppendRows"})count += 1}d.T.AppendRows(rows)
}func (d *Demo) AppendFooter() {d.T.AppendFooter(table.Row{"Total", "Total", "Total", "Total", count}, table.RowConfig{AutoMerge: true, AutoMergeAlign: text.AlignCenter})
}func (d *Demo) ColumnMerge() {d.T.SetColumnConfigs([]table.ColumnConfig{{Name: "AvgRtt",// Number是指定列的序号// Number: 5,AutoMerge: true,Align:     text.AlignCenter,},})
}func (d *Demo) SetAlignCenter() {column := []string{"IP", "Num", "PacketsRecv", "PacketLoss", "AvgRtt"}c := []table.ColumnConfig{}// 根据表格的列数循环进行设置，统一居中for i := 1; i <= len(column); i++ {name := column[i-1]if name == "AvgRtt" {c = append(c, table.ColumnConfig{Name:        "AvgRtt",AutoMerge:   true,Align:       text.AlignCenter,AlignHeader: text.AlignCenter,AlignFooter: text.AlignCenter,})continue}c = append(c, table.ColumnConfig{Name:        column[i],Align:       text.AlignCenter,AlignHeader: text.AlignCenter,AlignFooter: text.AlignCenter,})}d.T.SetColumnConfigs(c)
}func (d *Demo) SetWarnColor() {// 字体颜色WarnColor := text.Colors{text.BgRed}warnTransformer := text.Transformer(func(val interface{}) string {if val.(float64) > 0 {// 统计丢包服务器总数return WarnColor.Sprintf("%.2f%%", val)}return fmt.Sprintf("%v%%", val)})d.T.SetColumnConfigs([]table.ColumnConfig{{Name:        "PacketLoss",AutoMerge:   true,Align:       text.AlignCenter,AlignHeader: text.AlignCenter,AlignFooter: text.AlignCenter,Transformer: warnTransformer,},})
}func (d *Demo) Print() {fmt.Println(d.T.Render())
}func main() {demo := NewDemo()demo.MakeHeader()// demo.AddTitle()demo.AppendRow()demo.AppendRows()// demo.ColumnMerge()demo.AppendFooter()// demo.SetAlignCenter()demo.SetWarnColor()demo.Print()
}

结语

本文介绍了使用第三方库美化Golang的命令行表格格式化输出，除了table以外，go-pretty库中还包含了进度条、列表等美化方法，感兴趣可以自己看看官方文档。