I2C

Arduino

void requestEvent() {
  byte DEV_CNT =4;
  float hodnoty[DEV_CNT];
  hodnoty[0]=10000;
  hodnoty[1]=20;
  hodnoty[2]=1029.50;
  hodnoty[3]=3333.123456789;

 // Buffer to hold temp data, 4 bytes for each device

  byte buffer[DEV_CNT*4];


  // Populate buffer with temp. data
  for(int a = 0; a < DEV_CNT; a++) {
    byte* b = (byte*) &hodnoty[a];
    // 4 bytes for each float
    for(int i = 0; i < 4; i++) {
      buffer[a*4+i] = b[i];
    }
  }
  // Send data over i2c connection
  Wire.write(buffer, DEV_CNT*4);
}

Raspberry
#!/usr/bin/python
import smbus
import time
import struct

bus = smbus.SMBus(1)
address = 0x03

while True:
    try:
        data = bus.read_i2c_block_data(address, 0);
    except:
        print "Error getting data\n"
        continue
    # Example uses 4 sensors.
    # Each float from the Arduino is 4 bytes long.
    print len(data)
    print data
    for i in range(0, 4):
        bytes = data[4*i:4*i+4]
        # Python 2 struct.unpack takes the data to be unpacked
        # in string format, so the bytes need to be joined
        # together first
        print struct.unpack('f', "".join(map(chr, bytes)))[0]
    print
    time.sleep(5);