bitwise operand from python2.7 to python3.2.3

[Hove]

Using Model B 512MB, python3.2.3.3, 2014-01-07 wheezy raspbian
Does anyone knows how to convert from 2.7 to 3.2.3?

python2.x:

Code: Select all

data = (data & 0x0F)<< 4 #shift 4 bits to left 

I converted to python3.2.3:

Code: Select all

data = (data and 0x0F)<< 4 #shift 4 bits to left 

The error stating:
TypeError: unsigned operand type(s) for <<: 'NoneType' and 'int'

While I know nothing of Python 3, the use of 'and' instead of '&' as a bitwise operator is clearly incorrect. I suspect your Python 2 code is also correct in Python 3.

[croston]

What is 'data' and where did it come from?

[croston]

Ok more precise question - what is type(data) ?

You need to make sure that data is an integer.

[DougieLawson]

http://w8bh.net/pi/PiLCD3.pdf

When I wanted to run the code from one of Bruce Hall's PDFs I wrote an email to him (his address is in his PDF). He happily gave me a copy of his python code (for an 8x8 LED matrix in my case).

His code works just fine with Python 2. So I'd suspect you've introduced an error when you've cut 'n' pasted it from the PDF.

Why not write to Bruce?

[DougieLawson]

This is where semantic white space is a right royal pain in the tail.

Combine that with the fact that Adobe Reader can't preserve white space and you may as well print the PDF pages and type the program in by hand (the way we used to do ZX80, ZX81, ZX Spectrum programs in the 1980s when the Internet didn't exist).

[chrisryall]

coming from other languages, meaningful white space does seem pretty weird, and it is quite error/bug prone.

However it is what the language's progenitor wanted, we are stuck with it, and it does make the code look prettily "sepentine"

[DougieLawson]

coming from other languages, meaningful white space does seem pretty weird, and it is quite error/bug prone.

However it is what the language's progenitor wanted, we are stuck with it, and it does make the code look prettily "sepentine"

Agreed, but I'd like all those hours chasing stupid bugs back when it's four spaces or a missing tab that caused them.
The worse thing is the colon on the conditional statements. The number of snytux errurs I've had from missing that is driving me towards writing everything on the RPi in C.

[robbes]

The worse thing is the colon on the conditional statements. The number of snytux errurs I've had from missing that is driving me towards writing everything on the RPi in C.

Any decent Python IDE should pick that up.

[DougieLawson]

The worse thing is the colon on the conditional statements. The number of snytux errurs I've had from missing that is driving me towards writing everything on the RPi in C.

Any decent Python IDE should pick that up.

You're assuming I would ever want to use anything other than vi (or editpad on Windows) to create python. You're wrong!

[croston]

@DougieLawson - can we assume that you have never missed a semicolon off the end of a statement in C? What about curly brackets or lack of curly brackets in as part of an if statement in C?

You can write horribly obfuscated and unmaintainable code in C if you are a sloppy programmer!

[DougieLawson]

It's not a problem with vi and C, vi does matching of parentheses, brackets and braces.

If you want to see my sloppy code you should look at the COBOL I write.

[Hove]

I write all my Python using either vi (on my Pi) or visual slick on my Windows machine. The latter always corrupts the tabbing even if it's visually correct. The last thing I do before running my code is to tabify it in IDLE - takes only 30s and gets rid of all those so difficult to find spacing bugs.

[chrisryall]

That's fine, and yes we should use IT to control bugs and errors in iT

Just a bit unbeautiful to set up a language that needs this a priori. And a clash with the principle that you should be able to tell what code does just be reading it through?

But I can cope: Had to revisit an XSLT file i did for my son's web site last week … talk about "write only" coding (and I had coded it)! Python (new, chez moi) rocks, in comparison.

[keybeeper]

I used to write COBOL on special coding sheets and hand them to the punch-card girls for processing. The printed code was beautiful.

Now I find Geany very good for Python programming.

BTW why anyone writes new programs in Python2 is beyond me. I thought it was deprecated.

[rpdom]

I also used coding sheets to write programs in COBOL, but I didn't have to pass them to the punch room to be input as I had access to a terminal

The code was ugly, limited (although I found ways around some of that), and very long-winded. I preferred working in assembler whenever I could.