Why my light meter's values are blank on Arduino Serial Monitor? I tried to represent the values of TSL 2591 Adafruit light sensor on my Arduino Serial Monitor, but for some reason, I could not do that. The Arduino Serial Monitor just enters some blank values and scrolls down. 
Here is the code:

uint16_t x = tsl.getLuminosity(TSL2591_VISIBLE);
y = float(tsl.getLuminosity(TSL2591_VISIBLE));
z = (y, DEC);
Serial.write((byte)z);


x, y, and z are floats initially.
Use Serial.println(x); to print a number as text. Function write() sends the raw byte and Serial Monitor shows the character with that ASCII code, which is not valid or a not visible control character.



For the z = (y, DEC); from Wikipedia:


  In the C and C++ programming languages, the comma operator (represented by the token ,) is a binary operator that evaluates its first operand and discards the result, and then evaluates the second operand and returns this value (and type). 


so z is always 10 (value of constant DEC), which is ASCII code for the new line character