🌐 Mailman 3 January 2008 - 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.

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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

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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

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Re: [Tutor] Parsing DICOMRT file
by John Fouhy March 15, 2008

March 15, 2008

On 13/12/2007, Bryan Fodness <bryan.fodness(a)gmail.com> wrote: > I am new to doing anything like this. I have looked at > http://www.leadtools.com/SDK/Medical/DICOM/ltdc1.htm and am > not sure how to proceed. I haven't much experience here, but this is how I'd proceed, I think: 1. Start by reading the file. It's binary data (I guess) so there's no point in reading lines.: rawData = open('file.dcm', 'rb').read() 2. Write a function to parse the preamble: def parsePreamble(data): preamble = data[:128] dicm = data[128:132] # you might need to read up on encodings and things to make sure this test is valid if dicm == 'DICM': return preamble, 132 else: raise NotAPreambleException 3. Write functions to parse data elements. The functions are going to try to parse a data element starting at a particular position, and if successful, return the position of the end of the element. def parseDataelement(data, start): # do stuff -- the web page you linked didn't have enough information here return element, pos 4. Parse the whole thing; def parseDICOM(data): elements = [] try: preamble, next = parsePreamble(data) except NotAPreambleException: preamble, next = None, 0 while True: element, next = parseDataElement(data, next) elements.append(element) # you will need some way of breaking out of this loop, either by checking the structure of # element for an end condition, or by parseDataElement raising an exception. return elements # and maybe preamble too if you want it HTH!

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user-given variable names for objects
by Che M Feb. 28, 2008

Feb. 28, 2008

I'm sure this is a classic beginner's topic, and I've read a bit about it online already, but I'd like to ask about it here as well. I want to assign names to objects based on what a user inputs so that I can later keep track of them. In particular, I want to time multiple events by getting each of their start times and later comparing them to their respective stop times--I don't want to user timers. In order to do this, I need to give each start time a name associated with the name of the event. If there is an "event A" it's start time could be eventA_start, whereas event B could be called eventB_start, i.e.: eventA_start = datetime.datetime.now() The problem is, I don't know the "A" part...the user could choose eventPotato or eventDinosaur. I won't know in advance. I want the name chosen/inputted by the user to be attached to the name for the time that event started. I have read that the way to do this properly in Python is with use of dictionaries, but I haven't found a reference online that shows how to do it is in a complete way. Any help is appreciated. _________________________________________________________________ Share life as it happens with the new Windows Live. http://www.windowslive.com/share.html?ocid=TXT_TAGHM_Wave2_sharelife_122007

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results not quite 100 percent yet
by bhaaluu Feb. 21, 2008

Feb. 21, 2008

Greetings, I'm having a problem with the following test. I make a dictionary with 19 keys (1 to 19). Each key has a list of 7 numbers (A to G) # Set up the table # key# A B C D E F G tablE= {1:[ 0, 2, 0, 0, 0, 0, 0], # 1 2:[ 1, 3, 3, 0, 0, 0, 0], # 2 3:[ 2, 0, 5, 2, 0, 0, 0], # 3 4:[ 0, 5, 0, 0, 0, 0, 0], # 4 5:[ 4, 0, 0, 3,15,13, 0], # 5 6:[ 0, 0, 1, 0, 0, 0, 0], # 6 7:[ 0, 8, 0, 0, 0, 0, 0], # 7 8:[ 7,10, 0, 0, 0, 0, 0], # 8 9:[ 0,19, 0, 0, 0, 8, 0], # 9 10:[ 8, 0,11, 0, 0, 0, 0], # 10 11:[ 0, 0,10, 0, 0, 0, 0], # 11 12:[ 0, 0, 0,13, 0, 0, 0], # 12 13:[ 0, 0,12, 0, 5, 0, 0], # 13 14:[ 0,15,17, 0, 0, 0, 0], # 14 15:[14, 0, 0, 0, 0, 5, 0], # 15 16:[17, 0,19, 0, 0, 0, 0], # 16 17:[18,16, 0,14, 0, 0, 0], # 17 18:[ 0,17, 0, 0, 0, 0, 0], # 18 19:[ 9, 0, 0,16, 0, 0, 0]} # 19 # key# A B C D E F G The first loop is supposed to populate G with a random range of 4 integers 10 to 109 in random keys 1-19 that have a zero (except keY 6 and keY 11) So keY 6 and keY 11 should both have a zero in G after the four integers have been sown. # populate G column with range of 4 integers 10 to 109 # in random keys that have a zero [except keYs 6 and 11] print "%"*69 cnt=0 while cnt <= 3: print "CNT111=",cnt #debug-remove when done a = range(1,20) # 1 to 19 keY = random.choice(a) if keY == 6 or keY == 11 or tablE.values()[keY-1][6] != 0: tablE.values()[5][6] = 0 tablE.values()[10][6] = 0 cnt -= 1 keY = random.choice(a) if keY != 6 or keY != 11 or table.values()[keY-1][6] == 0: b = range(10,110) # 10 to 109 integer = random.choice(b) tablE.values()[keY-1][6] = integer cnt += 1 The second loop is supposed to populate G with numbers -4 to -1 in random keys 1-19 that have a zero (except keY 6 and keY11). So once again, 6 and 11 should have a zero in G after the loop is finished. # populate G with range of integers -1 to -4 # in random keYs that have a zero [except keYs 6 and 11] cnt=4 while cnt > 0: print "CNT222=",cnt a = range(1,20) if keY != 6 or keY != 11 and tablE.values()[keY-1][6] == 0: keY = random.choice(a) tablE.values()[keY-1][6] = -cnt cnt -= 1 if keY == 6 or keY == 11: tablE.values()[5][6] = 0 tablE.values()[10][6] = 0 cnt += 1 The last thing is that two integers are placed in specific keys 4 and 16, overwriting anything that may be in G whether a negative number or a number > 9. # Put an integer in G at two specific keys: 4 & 16 # These will overwrite anything placed there previously #a = range(1,99) #tablE.values()[3][6]= 100 + random.choice(a) #tablE.values()[15][6]= 100 + random.choice(a) The above has been commented out so I see if the two loops are each distributing four numbers each, without putting anything in G of keys 6 and 11. I've approached the problem by trying to get the loop to repeat if a number ends up in G at key 6 or key 11. I've done this changing the loop count. This seems to work about 97% of the time, or so. I'm looking for 100%. I know I can always just set those keys to zero before the table is written, but I'd rather have the table as fully populated by the two loops and just not have anything get in G in keys 6 & 11. Anyway, this is just a short test, part of a larger program. Here's the test code: #!/usr/bin/python import random print "\n"*30 # Set up the table # key# A B C D E F G tablE= {1:[ 0, 2, 0, 0, 0, 0, 0], # 1 2:[ 1, 3, 3, 0, 0, 0, 0], # 2 3:[ 2, 0, 5, 2, 0, 0, 0], # 3 4:[ 0, 5, 0, 0, 0, 0, 0], # 4 5:[ 4, 0, 0, 3,15,13, 0], # 5 6:[ 0, 0, 1, 0, 0, 0, 0], # 6 7:[ 0, 8, 0, 0, 0, 0, 0], # 7 8:[ 7,10, 0, 0, 0, 0, 0], # 8 9:[ 0,19, 0, 0, 0, 8, 0], # 9 10:[ 8, 0,11, 0, 0, 0, 0], # 10 11:[ 0, 0,10, 0, 0, 0, 0], # 11 12:[ 0, 0, 0,13, 0, 0, 0], # 12 13:[ 0, 0,12, 0, 5, 0, 0], # 13 14:[ 0,15,17, 0, 0, 0, 0], # 14 15:[14, 0, 0, 0, 0, 5, 0], # 15 16:[17, 0,19, 0, 0, 0, 0], # 16 17:[18,16, 0,14, 0, 0, 0], # 17 18:[ 0,17, 0, 0, 0, 0, 0], # 18 19:[ 9, 0, 0,16, 0, 0, 0]} # 19 # key# A B C D E F G # populate G column with range of 4 integers 10 to 109 # in random keys that have a zero [except keYs 6 and 11] print "%"*69 cnt=0 while cnt <= 3: print "CNT111=",cnt a = range(1,20) # 1 to 19 keY = random.choice(a) if keY == 6 or keY == 11 or tablE.values()[keY-1][6] != 0: tablE.values()[5][6] = 0 tablE.values()[10][6] = 0 cnt -= 1 keY = random.choice(a) if keY != 6 or keY != 11 or table.values()[keY-1][6] == 0: b = range(10,110) # 10 to 109 integer = random.choice(b) tablE.values()[keY-1][6] = integer cnt += 1 # populate G with range of integers -1 to -4 # in random keYs that have a zero [except keYs 6 and 11] cnt=4 while cnt > 0: print "CNT222=",cnt a = range(1,20) if keY != 6 or keY != 11 and tablE.values()[keY-1][6] == 0: keY = random.choice(a) tablE.values()[keY-1][6] = -cnt cnt -= 1 if keY == 6 or keY == 11: tablE.values()[5][6] = 0 tablE.values()[10][6] = 0 cnt += 1 # Put an integer in G at two specific keys: 4 & 16 # These will overwrite anything placed there previously #a = range(1,99) #tablE.values()[3][6]= 100 + random.choice(a) #tablE.values()[15][6]= 100 + random.choice(a) # print-out tablE print " data table" print "---------------------" print " values" print "key A B C D E F G" for roomNum in range(0,19): print " ",roomNum+1, for compass in range(0,7): xVal = tablE.values()[roomNum][compass] print xVal, if compass == 6: print I'm looking for suggestions on how to improve the two loops so that I get 100% distribution each time (eight numbers total). I'm running a GNU/Linux OS, Python 2.4.3 -- b h a a l u u at g m a i l dot c o m "You assist an evil system most effectively by obeying its orders and decrees. An evil system never deserves such allegiance. Allegiance to it means partaking of the evil. A good person will resist an evil system with his or her whole soul." [Mahatma Gandhi]

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creating a nested dictionary
by Garry Willgoose Feb. 1, 2008

Feb. 1, 2008

Is there any easy way to create a nested dictionary. I want to be able to allocate like pdb[dataset][modulename][parametername]['value']=value where dataset, modulename, parametername are variables that are determined within loops nested 3 deep, and value comes from a database call. Prior to the nested loops I do not know what the values of dataset, modulename, parametername will range over, but I do know pdb needs to be nested 3 deep. What I'd like to do is something like this pdb={} for dataset in dataset_list: modulename_list=getmodules(dataset) for modulename in modulename_list: parametername_list=getparameters(dataset,modulename) for parametername in parametername_list: value=getvalue(dataset, modulename, parametername) pdb[dataset][modulename][parametername]['value']=value What I'm currently doing is pdb={} for dataset in dataset_list: modulename_list=getmodules(dataset) moduledict={} for modulename in modulename_list: parametername_list=getparameters(dataset,modulename) valuedict={} for parametername in parametername_list: value=getvalue(dataset, modulename, parametername) valuedict['value']=value # valuedict needs to be a dictionary because there is other stuff valuedict['otherstuff]=otherstuff ... parameterdict[parametername]=valuedict.copy() moduledict[modeulename]=copy.deepcopy(parameterdict) pdb[dataset]=copy.deepcopy(moduledict) Now I know the 2nd is not that much more complex but this is a pretty common construct in what I'm doing so I'm just wondering if there is a clear and simple shortcut ;-) ==================================================================== Prof Garry Willgoose, Australian Professorial Fellow in Environmental Engineering, Director, Centre for Climate Impact Management (C2IM), School of Engineering, The University of Newcastle, Callaghan, 2308 Australia. Centre webpage: www.c2im.org.au Phone: (International) +61 2 4921 6050 (Tues-Fri AM); +61 2 6545 9574 (Fri PM-Mon) FAX: (International) +61 2 4921 6991 (Uni); +61 2 6545 9574 (personal and Telluric) Env. Engg. Secretary: (International) +61 2 4921 6042 email: garry.willgoose(a)newcastle.edu.au; g.willgoose(a)telluricresearch.com email-for-life: garry.willgoose(a)alum.mit.edu personal webpage: www.telluricresearch.com/garry ==================================================================== "Do not go where the path may lead, go instead where there is no path and leave a trail" Ralph Waldo Emerson ====================================================================

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How to compare the first line from multiple files
by Sorghum Crow Jan. 31, 2008

Jan. 31, 2008

How to compare the first line from multiple files Greetings, I'm new on the forum and relatively new to Python. I have been tasked at work with checking some files for consistency. What I need to do is verify that the first lines of a group of text files are identical. The files are all in the same directory. I know what the first line should be (or I can take the first line from the first file as the reference.) How would I go about doing this. Thanks in advance. Regards, Sorghum Crow

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Please comment on
by pee one Jan. 31, 2008

Jan. 31, 2008

Please comment on http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/543267 Thank you.

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how to use freeze for making executable python file in linux
by brindly sujith Jan. 31, 2008

Jan. 31, 2008

can i use freeze to make my python program in to executable in linux if yes...plz tell me how to use freeze whether i need to install something or its default in python

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