🌐 Mailman 3 October 2007 - Tutor - python.org

Send binary/hex data to a TCP socket
by Tod Haren July 19, 2011

July 19, 2011

I need to send a server at the other end of a socket a 36 byte "frame", where each byte represents a specific field in the custom data structure. (If there are any Ham operators reading this, I'm talking about the AGW Packet Engine) The documentation for the server says to initialize each field to a binary zero(0x00). How do I get a binary zero in Python? The next step is to send this all to the server and subsequently receive a similarly formated frame. A very basic frame looks something like this(modified from documentation): |00 00 00 00 4D 00 00 00 00 00 00 00 00 00 00 00 |....M........... |00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................ |00 00 00 00 |.... My problem is that hex(0) return '0x0' and hex(ord('M')) returns '0x4d'. If I concatonate these all together then the socket receives 109 bytes instead of 36. The documentation examples are in C++, so they are little help to me. The examples make use of the MoveMemory function for building the frames, but I'm clueless what that does. Pseudo code for the frame above: l = [] for i in xrange(36): l.append(hex(0)) l[4]=hex(ord('M')) d='' d=d.join(l) #I need some other data type to send besides a string! sock.send(d) #send the 36 bytes to the socket Any pointers or references would be greatly appreciated.

5 6

Tracking time
by Michael Key Jan. 6, 2010

Jan. 6, 2010

I am trying to develop a project tracking program that would allow you to track hours and minutes spent on several different projects and store he data in a database for printing. Any help would be appreciated. Mike

4 3

Learning Python
by Fred P Dec. 13, 2009

Dec. 13, 2009

Hey Everyone, I am completely new at python, but not new to programming or scripting. I have a couple of years of LUA scripting experience, about a year of C++ classes, and used to be very efficient at c-shell scripting in unix. My question for you guys: 1) How do I get Started? 2) Recommend any specific Books? 3) Any online tutors/ forums that would benefit a newbie 4) Any online classes that teach python? I have taken online c++ courses, and found them helpful. I was hoping to find something for python. My main objective is to write scripts for the following type of applications File management, file copies/syncs/ compares Text manipulation - like parsing text files to replace or augment specific values Integration into current applications to write redundant routines and maybe some day plugins I am not even sure what else, but I do know that every time i think of something that we need at work, other people say, "That would be a good task for a python script" and I would eventually like to be able to do something about that. Thanks Fred

5 5

difflib.SequenceMatcher with get_matching_blocks is incorrect
by Thomas Nov. 5, 2007

Nov. 5, 2007

I'm trying to write a program to test someone's typing speed and show them their mistakes. However I'm getting weird results when looking for the differences in longer (than 100 chars) strings: import difflib # a tape measure string (just makes it easier to locate a given index) a = '1-3-5-7-9-12-15-18-21-24-27-30-33-36-39-42-45-48-51-54-57-60-63-66-69-72-75-78-81-84-87-90-93-96-99-103-107-111-115-119-123-127-131-135-139-143-147-151-155-159-163-167-171-175-179-183-187-191-195--200' # now with a few mistakes b = '1-3-5-7-l-12-15-18-21-24-27-30-33-36-39o42-45-48-51-54-57-60-63-66-69-72-75-78-81-84-8k-90-93-96-9l-103-107-111-115-119-12b-1v7-131-135-139-143-147-151-m55-159-163-167-a71-175j179-183-187-191-195--200' s = difflib.SequenceMatcher(None, a ,b) ms = s.get_matching_blocks() print ms [(0, 0, 8), (200, 200, 0)] Have I made a mistake or is this function designed to give up when the input strings get too long? Thanks in advance, Thomas

2 1

'source' in python or preloading variables
by John Nov. 4, 2007

Nov. 4, 2007

I have a file sitelocations: STN_id[1]=AAA STNlat[1]=58.800000 STNlon[1]=17.400000 STNelv[1]=20 STN_id[2]=BBB STNlat[2]=42.450000 STNlon[2]=25.583333 STNelv[2]=2925 which in shell scripts I can simple 'source'. In Python I have to: sitesFile=file('sitelocations','r') sites=sitesFile.readlines() i=0; for l in sites: if i==0: STN_id.append(l.split('=')[1].strip('\n')); i+=1; elif i==1: STNlat.append(l.split('=')[1].strip('\n')); i+=1; elif i==2: STNlon.append(l.split('=')[1].strip('\n')); i+=1; else: STNelv.append(l.split('=')[1].strip('\n')); i=0; Is there a better way?? Thanks! -- Configuration `````````````````````````` Plone 2.5.3-final, CMF-1.6.4, Zope (Zope 2.9.7-final, python 2.4.4, linux2), Five 1.4.1, Python 2.4.4 (#1, Jul 3 2007, 22:58:17) [GCC 4.1.1 20070105 (Red Hat 4.1.1-51)], PIL 1.1.6

5 16

Inverted Index
by Dinesh B Vadhia Nov. 3, 2007

Nov. 3, 2007

Hello! Anyone know of any example/cookbook code for implementing inverted indexes? Cheers Dinesh

2 5

Build exe on Vista, have it run on XP?
by Michael Langford Nov. 2, 2007

Nov. 2, 2007

I'm trying to build a exe on a vista system using py2exe. It will deploy to vista and XP systems. If it matters, the application uses pyserial, as well. I have VS Studio 2005 installed on this laptop as well. I've found this so far that seems to be identical to what I'm seeing (for non-python programs): http://www.thescripts.com/forum/thread611031.html When I attempt to run, I get "The procedure entry point _except_handler4_common could not be located in the dynamic link library mscvrt.dll." Apparently vista has one more _except_handler#_common function than XP does. I've used py2exe several times before (however not recenty, as it was before Vista came out). I'm using a very basic setup file right now: from distutils.core import setup import py2exe setup(console=['responderbot.py']) Are there any ways to either py2exe work or any other exe builder for my build environment and deployment scenario? I don't really want to dig around in py2exe/pyserial internals to force it to use the dll's that the MS support person said it should be using. Will any automated exe builder work where I am? I've heard IronPython can compile down to an exe....is it a valid alternative? Should my CPython utility be compatible with ipy? I only use the random,time,sys, and serial modules. I really know nothing about ipy. --Michael -- Michael Langford Phone: 404-386-0495 Consulting: http://www.TierOneDesign.com/

2 3

Problem with msvcrt
by Ricardo Aráoz Nov. 1, 2007

Nov. 1, 2007

Hi, was just checking msvcrt module, tried a sample script : >>> import time >>> import msvcrt >>> while True : if msvcrt.kbhit() : key = msvcrt.getch() if key == 'h' : print 'Hello' if key == 'b' : print 'Bye' if key == '\r' : # <Enter> break else : time.sleep(0.1) < Now I keyboard 'h'..... nothing happens (an 'h' appears in idle) > < keyboard 'b'...... nothing still (a 'b' appears) > < keyboard <Enter>...... nothing > < keyboard <Ctrl>+<c> and then : Traceback (most recent call last): File "<pyshell#16>", line 11, in <module> time.sleep(0.1) KeyboardInterrupt hb >>> This is XP with 2.5 in Idle. Any ideas? Thx

2 2

question re type()
by Dick Moores Nov. 1, 2007

Nov. 1, 2007

I can't figure out how to test a variable n for its type. An example that is the wrong syntax, but shows what I want to do: if type(n) == 'int' or type(n) == 'long': do something elif type(n) == 'float': do something else elif type(n) == 'str': do something different What's the correct way? Thanks, Dick Moores

6 11

perplexing error with shelve
by Orest Kozyar Nov. 1, 2007

Nov. 1, 2007

I have a program which queries an online database (Medline) for XML data. It caches all data using shelve to avoid hitting the database too many times. For some reason, I keep getting a RuntimeError: maximum recursion depth exceeded when attempting to add a certain record. This program has successfully handled over 40,000 records from Medline, but for whatever reason, this particular record (PMID: 16842422) produces this error. If I set maximum recursion depth to a larger value such as 5,000, I get a segfault. Below is a script that should reproduce the problem I am having. Any guidance in solving this problem would greatly be appreciated. Thank you, Orest ####### START SCRIPT ####### import urllib, shelve from xml.dom import minidom baseurl = 'http://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?' params = { 'db': 'pubmed', 'retmode': 'xml', 'rettype': 'medline' } badkey = '16842422' goodkey = '16842423' #or just about any other ID data = shelve.open('data.tmp', writeback=True) try: params['id'] = goodkey url = baseurl + urllib.urlencode(params) doc = minidom.parseString(urllib.urlopen(url).read()) print 'Successfully retrieved and parsed XML document with ID %s' % goodkey data[goodkey] = doc print 'Successfully shelved XML document with ID %s' % goodkey except RuntimeError: print 'Should not see this error message!' try: params['id'] = badkey url = baseurl + urllib.urlencode(params) doc = minidom.parseString(urllib.urlopen(url).read()) print 'Successfully retrieved and parsed XML document with ID %s' % badkey data[badkey] = doc #Should not get this message! print 'Successfully shelved XML document with ID %s' % badkey except RuntimeError, e: print 'Error shelving XML document with ID %s' % badkey print e ####### END SCRIPT #######

6 12