CODEWITHSUNDEEP
python
Carlos Enrique Valdés
Carlos Enrique Valdés

Reputation: 57

String representation of an HEX array

Please i need some help, i have a python script that parses serial data, the data is stored on a byte array.

the problem, i ave an array with the string representation of a datetime:

bytearray['\x01','\x35','\x40','\x02','\x21','\x016']

meaning that the array represents 01:35:40 02/21/2016

how can i parse this array into a datetime i mean i can do this without a problem 

datetime.strptime('01:35:40 02/21/16', %H:%M:S %m/%d/%y)

but i cant get the freaking str representation out of that hex array

please help! thanks!

Upvotes: 1

Views: 277

Answers (1)

furas
furas

Reputation: 142859

Maybe it looks like strings but bytearray() keeps numbers (bytes) and you see their hex codes.

It looks like BCD (Binary-Coded Decimals) and you can easily convert to integers using bit operations

import datetime

b = bytearray('\x01\x35\x40\x02\x21\x16')

# decode BCD numbers    
n = [(x>>4)*10 + (x&15) for x in b]

# add 2000 to year
n[5] += 2000

# create datetime object
#d = datetime.datetime(year=n[5], month=n[3], day=n[4], hour=n[0], minute=n[1], second=n[2])
d = datetime.datetime(n[5], n[3], n[4], n[0], n[1], n[2])

# print it
print(d.strftime('%H:%M:%S %m/%d/%y'))

BTW: if you don't have Python bytearray() but normal list then you can use ord() 

b = ['\x01', '\x35', '\x40', '\x02', '\x21', '\x16']
b = [ord(x) for x in b]

# decode BCD numbers    
n = [(x>>4)*10 + (x&15) for x in b]

# ...

Upvotes: 1

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