Arduino code equivalent for python code binascii.unhexlify command

I want to convert ahexadecimal string to binary data.
For example, if i have a string like '424D368403', my output should be like b'BM6\x84\x03'.
The python code binascii.unhexlify('424D368403') gives the correct output.
But, I want to do this in arduino code.
Can someone help me in creating an arduino code / command in getting desired output?

What have you tried? What results has google shown you? I quick search will give you the answer.

If i understand the request, you want to convert the hex representation (2 hex chars per byte) of binary data bytes back to data bytes

So, for the hex string
“424D368403”

you want a 5 bytes array
byte myData = {0x42, 0x4D, 0x36, 0x84, 3};

If that is the case, you can use my function

bool hexToBin(const char *hexStr, byte *binBuf, const int binBufLen);

For example

byte myData[5];

hexToBin("424D368403", myData, 5);

Here is the code

// add the value of an hex digit to res
// if the supposed hexDigit is not an hex digit, return false
bool addHexDigitToInt(const char hexDigit, int *res)
{
  if (isdigit(hexDigit))  
  {
    *res += (hexDigit - '0');
    return true;
  }

  if (!isxdigit(hexDigit))
    return false;

  const char base = isupper(hexDigit) ? 'A' : 'a';
  
  *res += (hexDigit - base) + 10;
  return true;  
}

// convert two hex digits to an integer
// if one (or both) chars are not hex digits, return -1
int twoHexDigitToInt(const char *pHex)
{
  int res = 0;
  
  if (!addHexDigitToInt(*pHex, &res))
    return -1;

  res <<= 4;

  if (addHexDigitToInt(*(pHex + 1), &res))
    return res;

  return -1;
}

// convert the hex representation of a byte array back to a byte array
//
// parameters
//
//  hexStr = [input] hex string, must contain only hex digit (['0'-'9']['a'-'f']['A'-'F']), two hex digit per output byte
//  binBuf = [output] buffer for binary data
//  binBufLen = [input] len of binBuf in bytes, must be >= strlen(hexStr)/2
//
// return
//   true if conversion was successfull, false otherwise
//
bool hexToBin(const char *hexStr, byte *binBuf, const int binBufLen)
{
  int hexLen = strlen(hexStr);

  if (hexLen % 2)
    // the input string contains an odd number of hex chars
    return false;

  if (binBufLen < hexLen/2)
    // the output buffer can't store all the data
    return false;

  const char *pHex = hexStr;
  byte *pBuf = binBuf;
  
  for (int i=0; i < hexLen; i+=2)
  {
    int nextVal = twoHexDigitToInt(pHex+i);

    if (nextVal < 0)
      return false;

    *pBuf = (byte)nextVal;  
    pBuf++;
  }

  return true;
}

why not just use strtol() rather than reinvent the wheel?