Anyone know Python?

[Beerina]

When I read some binary data with pySerial, I get an str that contains elements that, when printed, look like this:

'\xc0'


That itself is a str. How do I turn it back into a number so I can do math on it?

o int( '\xc0' ) chokes

o The binascii library is useless as it can't handle this in any of its format conversions.


As these are bytes, I could conceivably do 256-sized lookup table, but that's obviously stupid to do.



I am not super familiar with Python, yet, having only started a few days ago.

The result should be amenable to simple math, like adding or subtracting 3.

 

[Paul C. Anagnostopoulos]

The ord() method returns the Unicode code for the character in a string of length 1. I think that should do the trick.

~~ Paul

 

[Beerina]

Byte array objects, pickler, jeebus...



ord('\xc0') ==> 192


Thanks, Paul!

 

[Paul C. Anagnostopoulos]

It all pales into insignificance against the backdrop of a whitespace language.

for n in range(2, 10):
   for x in range(2, n):
      if n % x == 0:
        print n, 'equals', x, '*', n/x
print tracing info
        break
   else:
      print n, 'is a prime number'

Screwed and screwed again.

~~ Paul

 

[Beerina]

Ahh, another question, If I may?


Wut?

>>> class abc:
	def __init__(self):
		print "abc.__init__ called!"

>>> x = abc.abc()

Traceback (most recent call last):
  File "<pyshell#45>", line 1, in <module>
    x = abc.abc()
AttributeError: class abc has no attribute 'abc'
>>> x = abc.__class()

Traceback (most recent call last):
  File "<pyshell#46>", line 1, in <module>
    x = abc.__class__()
AttributeError: class abc has no attribute '__class__'
>>>

Ok, figured it out. The reason is Dive Into Python, the online tutorial, saves their class in a module named the same thing, but with lower case for module name.

This works:

>>> x = abc()
abc.__init__ called!
>>> x
<__main__.abc instance at 0x011C2D78>
>>>

Apparently the Dive Into Python example was thus doing the equivalent of x = ABC.abc(), where the first abc is the module name.

 

[Greediguts]

Damn, I thought the OP meant I could quote lines from the "Holy Grail" and such....


Wrong Python....

 

[Beerina]

>>> for n in range(1,100):
	print "Spam"

Spam
Spam
Spam
Spam
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>>>

 

[Beerina]

Ok, next question:

I am trying to use makepy.py to access a COM-interfaced library.

Several web sites say to do this to see what's available:

e.g. here:

Example using Microsoft Office 97.

Either:

Run 'win32com\client\makepy.py' (eg, run it from the command window, or double-click on it) and a list will be presented. Select the Type Library 'Microsoft Word 8.0 Object Library'

But I get this:

>>> import win32com.client
>>> win32com\client\makepy.py <---- Red rectangle starts after the y in .py
SyntaxError: unexpected character after line continuation character
>>>


makepy.py exists in the relevant win32com\client directory "C:\Python26\Lib\site-packages\win32com\client"



Any ideas? I get the same result typing the line in manually, in case copy-paste from the web site captured some bizarre character codes.


Note I am not looking for a general tutorial on COM and Python (that's what that page is) just wondering about what I could be doing wrong.

 

[Beerina]

Well, you have to run it from the command prompt:

C:\Python26\Lib\site-packages\win32com\client\makepy.py

 

[kylev]

This simply isn't valid python:

>>> win32com\client\makepy.py

If you're trying to run that, you need to do it from a command prompt, not a Python interactive prompt.

 

[KirinDave]

It all pales into insignificance against the backdrop of a whitespace language.

for n in range(2, 10):
   for x in range(2, n):
      if n % x == 0:
        print n, 'equals', x, '*', n/x
print tracing info
        break
   else:
      print n, 'is a prime number'

Screwed and screwed again.

~~ Paul

Hey wow. There might be sane compsci types here. Down with significant whitespace. Down with that puny lambda.

 

[NobbyNobbs]

I don't know the first thing about programming, but I'd like to put a plug in for my best friend, Mark Pilgrim, who wrote a book (several, actually) called Dive Into Python. He's quite a good writer. It's available in print or online. Google it, and him.