Leading zero for hex string

Question

I read UART port with this:

print ("Attempt to Read") readOut = serial_port.readline() time.sleep(1) in_hex = hex(int.from_bytes(readOut,byteorder='big')) print ("Reading: ", in_hex)

and then it gives me output e.g. like:

Attempt to Read Reading: 0x6011401011403

So there is one leading zero missing before number 6. I can't find a way to add it without specifying in the code the length of the whole string (and I don't want to do that, becasue the string can have variable length e.g. like 0x056822). Could you please help?

What is readOut in this example? What makes you know a leading 0 is missing? — liamhawkins
– liamhawkins, Commented Mar 29, 2019 at 18:11
I read it from UART interface and in the above example readOut should have 7 bytes, so I would like to print it like: 0x06011401011403 — bLAZ
– bLAZ, Commented Mar 29, 2019 at 18:14

Alain T. · Accepted Answer · 2019-03-29 18:30:01Z

1

You could inject a zero after 0x when the number of characters is odd:

if len(in_hex)%2: in_hex = in_hex.replace("0x","0x0")

answered Mar 29, 2019 at 18:30

Alain T.

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1 Comment

bLAZ Over a year ago

Omg, simple and clever. I definitely should take a break today. Thank you!

VPfB · Accepted Answer · 2019-03-29 19:33:18Z

Even number of digits is guaranteed if you convert each byte to two characters:

hexstr = ''.join(format(b,'02x') for b in bytesequence)

Just prepend "0x" if you want.

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