Hallo,
fang mal bei Adam und Eva an . Versuch mal den hier und berichte
String a="%221,%222,%223,%224,%225";
String b=a;
String c=a;
String d=a;
void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
Serial.println(a);
a.replace("%",""); Serial.println(a);
b.replace("%2",""); Serial.println(b);
c.replace("%22",""); Serial.println(c);
}
void loop() {
// put your main code here, to run repeatedly:
}