Diff. between Py 2.7 and 3

[ebolisa]

Hi,

The following code gets the wifi quality type on a raspberry pi and works with 2.7 but not with 3.0.

The error generated is

Traceback (most recent call last):
File "test.py", line 9, in <module>
if line.startswith("Quality"):
TypeError: startswith first arg must be bytes or a tuple of bytes, not str

The startswith method used is correct based on the manual
str.startswith(str, beg = 0,end = len(string));
so, not sure where the error is.

I appreciate some insights.
TIA

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from subprocess import check_output   '''get wifi connection printout''' scanoutput = check_output(["iwlist", "wlan0", "scan"])   '''separate bytes''' for line in scanoutput.split():   '''filter the quality line out'''   if line.startswith("Quality"):      '''remove text from it'''      level = line.split('=')[1]      '''get the divisor'''      lev0 = float(level.split('/')[0])      '''get the divident'''      lev1 = float(level.split('/')[1])      '''devide and multiply by 100 to get the %'''      cal = int(lev0 / lev1) * 100      print("{}%".format(str(cal)))

[snippsat]

Received data a for check_output() will be bytes,so need to decode() to string.
Example:

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>>> s = b'Quality is good' >>> if s.startswith('Quality'): ...     print('True') ...     Traceback (most recent call last):   File "<interactive input>", line 1, in <module> TypeError: startswith first arg must be bytes or a tuple of bytes, not str   >>> # Fix >>> s = s.decode() #same as s.decode('utf-8') >>> if s.startswith('Quality'): ...     print('True') ...     True

[ebolisa]

Fixed it, Thank you!!