Determine number of items in csv file by arduino

[sjorsb]

Dear all,
Im struggling with the following:

I need to determine the number of items per line in a csv file.
The arduino is reading a csv file from an sdcard.
The csv file is semicolon separated, (
Before i can work with the values from a record ( gathered via parseint() its imperatie to know how many values there are in a record (one line)

The csv file can be updated once and a while, and that should not result in update the sketch in the arduino.

Therefore i need a piece of as simple as possible code to read the number of values per record during setup.
There should be a smart trick to count the number of semicolums in a line for instance

Please help!

Kind regards

Sjors

[jhaine]

Start a count at 0; scan the line character by character, each time add 1 to the count; stop when you reach end of line. Maybe not smart but obvious.

[UKHeliBob]

Do you mean something like this ?

void setup()
{
  Serial.begin(115200);
  Serial.println(countItems("1;2;3;4;5;6;"));
  Serial.println(countItems("Mary;had;a;little;lamb"));
}

void loop()
{
}

byte countItems(char * line)
{
  Serial.println(line);
  byte count = 0;
  for (int c = 0; c < strlen(line); c++)
  {
    if (line[c] == ';')
    {
      count++;
    }
  }
  return count;
}

[cedarlakeinstruments]

@UKHeliBob

byte count = 0;

Remember there's one more value after the last semicolon, so you should initialize count to 1.

[UKHeliBob]

As usual the Devil is in the detail. For instance we don't know whether the data will always end in a semicolon, never end in a semicolon or will sometimes end in a semicolon

Good point. It would, of course, help to know the exact format of the data such as whether it always ends in a semicolon, never ends in a semicolon or sometimes ends in a semicolon

Meanwhile, consider this revised version of the code

void setup()
{
  Serial.begin(115200);
  Serial.println(countItems("1;2;3;4;5;6;"));
  Serial.println(countItems("Mary;had;a;little;lamb"));
  Serial.println(countItems(""));
}

void loop()
{
}

byte countItems(char * line)
{
  Serial.println(line);
  if (strlen(line) == 0)
  {
    return 0;
  }
  byte count = 1;
  for (int c = 0; c < strlen(line); c++)
  {
    if (line[c] == ';')
    {
      count++;
    }
  }
  if (line[strlen(line) - 1] == ';') // ends with a semicolon
  {
    count--;;
  }
  return count;
}