如何以易读的方式打印地图、结构体或其他内容?
使用 PHP,您可以这样做。
echo '<pre>';
print_r($var);
echo '</pre>';
或者header('content-type: text/plain');
print_r($var);
如何以易读的方式打印地图、结构体或其他内容?
使用 PHP,您可以这样做。
echo '<pre>';
print_r($var);
echo '</pre>';
或者header('content-type: text/plain');
print_r($var);
使用Go语言的fmt
包。例如,
package main
import "fmt"
func main() {
variable := "var"
fmt.Println(variable)
fmt.Printf("%#v\n", variable)
header := map[string]string{"content-type": "text/plain"}
fmt.Println(header)
fmt.Printf("%#v\n", header)
}
输出:
var
"var"
map[content-type:text/plain]
map[string]string{"content-type":"text/plain"}
import "fmt"
Overview
Package fmt implements formatted I/O with functions analogous to C's printf and scanf. The format 'verbs' are derived from C's but are simpler.
%+v
和%v
。 - AndrewN我认为在很多情况下,使用"%v"就足够简洁了:
fmt.Printf("%v", myVar)
来自 fmt 包文档页面:
%v 以默认格式打印值。 当打印结构体时,加号标志 (%+v) 添加字段名称。
%#v 以 Go 语法表示值。
这里是一个例子:
package main
import "fmt"
func main() {
// Define a struct, slice and map
type Employee struct {
id int
name string
age int
}
var eSlice []Employee
var eMap map[int]Employee
e1 := Employee{1, "Alex", 20}
e2 := Employee{2, "Jack", 30}
fmt.Printf("%v\n", e1)
// output: {1 Alex 20}
fmt.Printf("%+v\n", e1)
// output: {id:1 name:Alex age:20}
fmt.Printf("%#v\n", e1)
// output: main.Employee{id:1, name:"Alex", age:20}
eSlice = append(eSlice, e1, e2)
fmt.Printf("%v\n", eSlice)
// output: [{1 Alex 20} {2 Jack 30}]
fmt.Printf("%#v\n", eSlice)
// output: []main.Employee{main.Employee{id:1, name:"Alex", age:20}, main.Employee{id:2, name:"Jack", age:30}}
eMap = make(map[int]Employee)
eMap[1] = e1
eMap[2] = e2
fmt.Printf("%v\n", eMap)
// output: map[1:{1 Alex 20} 2:{2 Jack 30}]
fmt.Printf("%#v\n", eMap)
// output: map[int]main.Employee{1:main.Employee{id:1, name:"Alex", age:20}, 2:main.Employee{id:2, name:"Jack", age:30}}
}
fmt.Println()
进行打印。您需要导入“fmt”包(请参见下面的示例)。许多数据类型可以直接打印输出。如果想要为自定义类型获取易于阅读的打印输出,则需要为该类型定义String() string
方法。package main
import "fmt"
// No `String()` method
type UnstringablePerson struct {
Age int
Name string
}
// Has a `String()` method
type StringablePerson struct {
Age int
Name string
}
// Let's define a String() method for StringablePerson, so any instances
// of StringablePerson can be printed how we like
func (p *StringablePerson) String() string {
return fmt.Sprintf("%s, age %d", p.Name, p.Age)
}
func main() {
// Bobby's type is UnstringablePerson; there is no String() method
// defined for this type, so his printout will not be very friendly
bobby := &UnstringablePerson{
Age: 10,
Name: "Bobby",
}
// Ralph's type is StringablePerson; there *is* a String() method
// defined for this type, so his printout *will* be very friendly
ralph := &StringablePerson{
Age: 12,
Name: "Ralph",
}
fmt.Println(bobby) // prints: &{10 Bobby}
fmt.Println(ralph) // prints: Ralph, age 12
}
fmt.Printf("%v", whatever)
在Go语言中,%v
类似于PHP中的print_r()、var_dump()和var_export()函数。(%v
是重要的一部分)。
祝你好运!
我用这个来调试:
func printVars(w io.Writer, writePre bool, vars ...interface{}) {
if writePre {
io.WriteString(w, "<pre>\n")
}
for i, v := range vars {
fmt.Fprintf(w, "» item %d type %T:\n", i, v)
j, err := json.MarshalIndent(v, "", " ")
switch {
case err != nil:
fmt.Fprintf(w, "error: %v", err)
case len(j) < 3: // {}, empty struct maybe or empty string, usually mean unexported struct fields
w.Write([]byte(html.EscapeString(fmt.Sprintf("%+v", v))))
default:
w.Write(j)
}
w.Write([]byte("\n\n"))
}
if writePre {
io.WriteString(w, "</pre>\n")
}
}
html/template
,它可以进行适当的转义处理。你上面编写的代码容易受到简单的注入攻击。别这样做。 :P - dyoo