How can I create byte values from integers in Python?

Question

How can I create byte values from integers in Python?

Background: I need to send a numeric value as a byte to an external device, but I am facing a problem. My code:

ser=serial.Serial("COM3",9600, timeout=0)
ser.write(value)

where "value" is the int I read, read. The problem is, when I post this, it sends the character value, not the actual value (it sends byte value 31 for number 5, since that's the unicode position for it, I believe)

In fact, I want to be able to send it the character "\ x05", for example. I guess my question is how would I convert both int 5 to char "\ x05", or 37 to "\ x37"

+3

python serial-port arduino pyserial

mattdee123 10 Mar 12 at 9:02 am

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2 answers

Amber · Answer 1 · 2012-03-10T09:05:07+0000

Use the built-in function chr()

.

If you have a list of such integers that you need to send, you can use bytearray()

.

Alternatively, in newer versions of Python, you can simply use type byte

.

shofee · Answer 2 · 2012-03-10T09:12:17+0000

you can use this.

bytes(chr(my_int))    # not strictly correct unless 0<=my_int<=255
bytes((my_int,))

How can I create byte values ​​from integers in Python?

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How can I create byte values from integers in Python?