我目前有一个 Go 代码，可以订阅和打印发布到某个主题的传感器数据。这是我的代码：
package main
import (
"crypto/tls"
"flag"
"fmt"
//"log"
"os"
"os/signal"
"strconv"
"syscall"
"time"
MQTT "github.com/eclipse/paho.mqtt.golang"
)
func onMessageReceived(client MQTT.Client, message MQTT.Message) {
//fmt.Printf("Received message on topic: %s\nMessage: %s\n", message.Topic(), message.Payload())
fmt.Printf("%s\n", message.Payload())
}
func main() {
//MQTT.DEBUG = log.New(os.Stdout, "", 0)
//MQTT.ERROR = log.New(os.Stdout, "", 0)
c := make(chan os.Signal, 1)
signal.Notify(c, os.Interrupt, syscall.SIGTERM)
hostname, _ := os.Hostname()
server := flag.String("server", "tcp://test.mosquitto.org:1883", "The full url of the MQTT server to connect to ex: tcp://127.0.0.1:1883")
topic := flag.String("topic", …我目前有一个MQTT代码,可以订阅主题,打印出收到的消息,然后将更多指令发布到新主题.在订阅/打印在一个够程完成,出版在另一个goroutine中进行.这是我的代码:
var wg, pg sync.WaitGroup
// All messages are handled here - printing published messages and publishing new messages
var f MQTT.MessageHandler = func(client MQTT.Client, msg MQTT.Message) {
wg.Add(1)
pg.Add(1)
go func() {
defer wg.Done()
fmt.Printf("%s\n", msg.Payload())
//fmt.Println(os.Getpid())
}()
go func(){
defer pg.Done()
message := ""
//Changing configurations
if strings.Contains(string(msg.Payload()), "arduinoLED") == true {
message = fmt.Sprintf("change configuration")
}
if strings.Contains(string(msg.Payload()), "NAME CHANGED") == true{
message = fmt.Sprintf("change back")
}
// Publish further instructions to "sensor/instruction" …我想检查我传递的值是否是浮点数。我有一段代码可以检查它是某个字符串还是浮点数。如果两者都不是，则给出错误。这是代码：
if sensorData.Passport.Geolocation.Latitude != "gps" && sensorData.Passport.Geolocation.Latitude != "internet" && sensorData.Passport.Geolocation.Latitude != "unknown" && sensorData.Passport.Geolocation.Latitude != //a float nmber{
fmt.Println("Incorrect option")
}
如何检查数据是否为浮点数？