Splitting up a string with a delimiter and storing each "cut" in an array

Projects Programming
1

I have a project where I have some data come in and I then splice it at the commas.

(Shortened Code)

char buf[sizeof(dummydata)];
serialResponse.toCharArray(buf, sizeof(buf));
char *p = buf;
char *str;
while ((str = strtok_r(p, ",", &p)) != NULL) // delimiter is the comma
Serial.println(str);

serialResponse is the variable containing the data I received.

When I run the code, it prints out each segment on a new line in the serial monitor, but I have no idea how to store it in an array.

EX:
If I receive "123,456,789,abc,def,ghi", I want the array to have "123" as the first entry, "456" as the second etc.

Any help is greatly appreciated

2

Does this do what you want? The strings array has pointers to the parts.

char array[] = "123,456,789,abc,def,ghi";
char *strings[10];
char *ptr = NULL;

void setup()
{
    Serial.begin(115200);
    //Serial.print(array);
    byte index = 0;
    ptr = strtok(array, ",");
    while(ptr != NULL)
    {
        strings[index] = ptr;
        index++;
        ptr = strtok(NULL, ",");
    }
    //Serial.println(index);
    for(int n = 0; n < index; n++)
   { 
    Serial.println(strings[n]);
   }
   Serial.print(" the second entry = ");
   Serial.println(strings[1]);
}

void loop()
{
    // put your main code here, to run repeatedly:

}

edit: changed to use OP input array

3 
Serial.println(str);

Instead of (or as well as) this do something like

strcpy(theArray[index++], str)  //copy the string to the array and increment the array index

You will, of course, need to declare and initialise the array and array index variables before doing this

4

groundFungus:
Does this do what you want? The strings array has pointers to the parts.

char array[] = "123,456,789,abc,def,ghi";

char *strings[10];
char *ptr = NULL;

void setup()
{
   Serial.begin(115200);
   //Serial.print(array);
   byte index = 0;
   ptr = strtok(array, ",");
   while(ptr != NULL)
   {
       strings[index] = ptr;
       index++;
       ptr = strtok(NULL, ",");
   }
   //Serial.println(index);
   for(int n = 0; n < index; n++)
  {
   Serial.println(strings[n]);
  }
  Serial.print(" the second entry = ");
  Serial.println(strings[1]);
}

void loop()
{
   // put your main code here, to run repeatedly:

}



edit: changed to use OP input array

Yes, this does what I want but I have a String that I need to separate and put each piece in its own index.
So the String "abc,123,987" would turn into an array with abc at index 0, 123 at 1, and 987 at 2

Sorry for the confusion.

As for UKHeliBob's answer, it causes the incoming data to be truncated before I even do anything with it and it sometimes doesn't even show up.

5

have a String that I need to separate and put each piece in its own index.

Do you mean you have a String or that you have a string ?
Not the same thing at all

6

String

7

"I have a project where I have some data come in and I then splice it at the commas."

Parsing Strings is fairly simple. If you have control over the way the data is sent, then that is a big help on sorting the data out on the receiving end. Use the forum Google search function in the upper right of this page to search for "parse String" and similar key words. You will probably find many previous project discussions and code showing various methods.

8

Are you aware of the potential pitfalls of using the String class with Arduino?

9

Yes.

10

"If I receive "123,456,789,abc,def,ghi", I want the array to have "123" as the first entry, "456" as the second etc."

Some test code from way back where a comma delineated string of characters is saved as a String, then parsed and the parts saved as variables. several ways doing parsing, depending on how the initial data is packaged and sent.

//zoomkat 11-12-13 String capture and parsing  
//from serial port input (via serial monitor)
//and print result out serial port
//copy test strings and use ctrl/v to paste in
//serial monitor if desired
// * is used as the data string delimiter
// , is used to delimit individual data 

String readString; //main captured String 
String angle; //data String
String fuel;
String speed1;
String altidude;

int ind1; // , locations
int ind2;
int ind3;
int ind4;
 
void setup() {
  Serial.begin(9600);
  Serial.println("serial delimit test 11-12-13"); // so I can keep track of what is loaded
}

void loop() {

  //expect a string like 90,low,15.6,125*
  //or 130,hi,7.2,389*

  if (Serial.available())  {
    char c = Serial.read();  //gets one byte from serial buffer
    delay(3);  //small delay to allow input buffer to fill
    if (c == '*') {
      //do stuff
      
      Serial.println();
      Serial.print("captured String is : "); 
      Serial.println(readString); //prints string to serial port out
      
      ind1 = readString.indexOf(',');  //finds location of first ,
      angle = readString.substring(0, ind1);   //captures first data String
      ind2 = readString.indexOf(',', ind1+1 );   //finds location of second ,
      fuel = readString.substring(ind1+1, ind2+1);   //captures second data String
      ind3 = readString.indexOf(',', ind2+1 );
      speed1 = readString.substring(ind2+1, ind3+1);
      ind4 = readString.indexOf(',', ind3+1 );
      altidude = readString.substring(ind3+1); //captures remain part of data after last ,

      Serial.print("angle = ");
      Serial.println(angle); 
      Serial.print("fuel = ");
      Serial.println(fuel);
      Serial.print("speed = ");
      Serial.println(speed1);
      Serial.print("altidude = ");
      Serial.println(altidude);
      Serial.println();
      Serial.println();
      
      readString=""; //clears variable for new input
      angle="";
      fuel="";
      speed1="";
      altidude="";
    }  
    else {     
      readString += c; //makes the string readString
    }
  }
}
11

Thanks everyone for your help! I solved it using mainly zoomkat's code, with slight modification to my needs.