Re: Partitioning a list
On Wed, 22 Aug 2018 at 00:44, Poul Riis wrote: > > I would like to list all possible ways to put N students in groups of k > students (suppose that k divides N) with the restriction that no two students > should ever meet each other in more than one group. > I think this is a classical problem and I think there must be a python > solution out there but I cannot find it. For instance, numpy's array_split > only lists one (trivial) split. > I would be happy if someone could refer me to a general python algorithm > solving the problem. The basic problem seems to be a simple case of looking for combinations of k items from N, which is something itertools can help you with. I don't understand the restriction (or at least, if I understand the basic requirement then the restriction makes no sense to me, as a set of combinations only puts any one student in one group, so "meeting someone in more than one group" isn't possible). But what I'd be inclined to do, at least as a first approach (refine it if it's too slow for your real case) is to take each basic solution, and check if it satisfies the extra constraint - keep the ones that do. Combinatorial problems typically grow very fast as N (and/or k) increase, so that approach may not work as a practical solution, but it will at least mean that you code your requirement in an executable form (which you can test for small numbers) and then you'll have a more precise problem to describe when looking for help tuning it. Paul -- https://mail.python.org/mailman/listinfo/python-list
Re: Saving application configuration to the ini file respecting order of sections/options and providing mechanism for (nested) complex objects
Thanks. As I can see python 3.7 is the best option. Thank you very very muchs for the code as well. Best regards. -- https://mail.python.org/mailman/listinfo/python-list
zpifile.py error - no crc 32 attribute
Hi guys, I have a problem with zipfile and zlib module, and hope to get some help. That's my error: "import zipfile File "/home/lib/python3.7/lib/python3.7/zipfile.py", line 19, in crc32 = zlib.crc32 AttributeError: module 'zlib' has no attribute 'crc32' " I have no idea what to do with that :/ I use this version of zipfile: https://github.com/python/cpython/blob/3.7/Lib/zipfile.py Somebody knows how to solve it? Regards -- https://mail.python.org/mailman/listinfo/python-list
Re: Partitioning a list
> On Aug 22, 2018, at 8:51 AM, Paul Moore wrote: > >> On Wed, 22 Aug 2018 at 00:44, Poul Riis wrote: >> >> I would like to list all possible ways to put N students in groups of k >> students (suppose that k divides N) with the restriction that no two >> students should ever meet each other in more than one group. >> I think this is a classical problem and I think there must be a python >> solution out there but I cannot find it. For instance, numpy's array_split >> only lists one (trivial) split. >> I would be happy if someone could refer me to a general python algorithm >> solving the problem. > > The basic problem seems to be a simple case of looking for > combinations of k items from N, which is something itertools can help > you with. I don't understand the restriction (or at least, if I > understand the basic requirement then the restriction makes no sense > to me, as a set of combinations only puts any one student in one > group, so "meeting someone in more than one group" isn't possible). > But what I'd be inclined to do, at least as a first approach (refine > it if it's too slow for your real case) is to take each basic > solution, and check if it satisfies the extra constraint - keep the > ones that do. > > Combinatorial problems typically grow very fast as N (and/or k) > increase, so that approach may not work as a practical solution, but > it will at least mean that you code your requirement in an executable > form (which you can test for small numbers) and then you'll have a > more precise problem to describe when looking for help tuning it. > > Paul > Paul, my understanding of the problem is that you want to create multiple divisions of the larger group into smaller groups, such that if two people are in the same group in 1 division, they never appear together in other divisions. One sample problem which I have had to solve with a similar restriction (but in my case was to minimize not eliminate repeats) was scheduling races. Say you have 9 cars you want to race in triples, and no pair of cars should ever meet twice. One option would be the following matches: 1,2,3; 4,5,6; 7,8,9 1,4,7; 2,5,8; 3,6,9 1,5,9; 2,6,7; 3,4,8 1,6,8; 2,4,9; 3,5,7 You can show this is the most number of triples you can get out of 9, as every number has been paired with every other number once, so to create another triple, you must get a duplicate pairing. I don’t know of any general algorithm to generate these. -- https://mail.python.org/mailman/listinfo/python-list
Re: zpifile.py error - no crc 32 attribute
On Wed, 22 Aug 2018 13:12:59 +0200, jacob m wrote: [snip] > That's my error: > "import zipfile > File "/home/lib/python3.7/lib/python3.7/zipfile.py", line 19, in > crc32 = zlib.crc32 > AttributeError: module 'zlib' has no attribute 'crc32' " > > I have no idea what to do with that :/ I use this version of zipfile: > https://github.com/python/cpython/blob/3.7/Lib/zipfile.py > > Somebody knows how to solve it? zipfile imports zlib and expects zlib to define something called crc32. On your system, for some reason, the zlib that's being imported doesn't define anything called crc32. Is there perhaps a different zlib on your path, hiding the real zlib? -- To email me, substitute nowhere->runbox, invalid->com. -- https://mail.python.org/mailman/listinfo/python-list
Re: zpifile.py error - no crc 32 attribute
Hi, " Is there perhaps a different zlib on your path, hiding the real zlib?" - I'm unsure of that. "sudo apt-get install zlib1g-dev Reading package lists... Done Building dependency tree Reading state information... Done zlib1g-dev is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded." Regards On 22 August 2018 at 13:12, jacob m wrote: > Hi guys, > I have a problem with zipfile and zlib module, and hope to get some help. > > That's my error: > "import zipfile > File "/home/lib/python3.7/lib/python3.7/zipfile.py", line 19, in > > crc32 = zlib.crc32 > AttributeError: module 'zlib' has no attribute 'crc32' " > > I have no idea what to do with that :/ I use this version of zipfile: > https://github.com/python/cpython/blob/3.7/Lib/zipfile.py > > Somebody knows how to solve it? > Regards > > -- https://mail.python.org/mailman/listinfo/python-list
Re: Partitioning a list
On Wed, 22 Aug 2018 at 17:33, Richard Damon wrote: > Paul, my understanding of the problem is that you want to create multiple > divisions of the larger group into smaller groups, such that if two people > are in the same group in 1 division, they never appear together in other > divisions. > > One sample problem which I have had to solve with a similar restriction (but > in my case was to minimize not eliminate repeats) was scheduling races. Say > you have 9 cars you want to race in triples, and no pair of cars should ever > meet twice. One option would be the following matches: > 1,2,3; 4,5,6; 7,8,9 > 1,4,7; 2,5,8; 3,6,9 > 1,5,9; 2,6,7; 3,4,8 > 1,6,8; 2,4,9; 3,5,7 > You can show this is the most number of triples you can get out of 9, as > every number has been paired with every other number once, so to create > another triple, you must get a duplicate pairing. > I don’t know of any general algorithm to generate these. I don't know of a general algorithm for that either. What I'd do is: 1. Generate all the combinations 2. Run through them, keeping track of all pairings we've seen in already-accepted combinations 3. If the new combination has no "already seen" pairings, yield it and add its pairings to the set of already seen ones, otherwise skip it. I think that gives the expected result. Paul -- https://mail.python.org/mailman/listinfo/python-list
What is the pattern?
I asked this before but my Usenet reader only saves messages for 30
days. I still can't get the pattern for this chart.
I started working on the code that should print it, but I never
remembered how to do it.
empire={6:"Infantry",12:"Armor/Fighter",30:"Transport"}
for x in range (6,120,6):
print(x,x - x / 6)
Anyone want to fill in the blanks to give this chart?
https://imgur.com/a/OR0WKsv
--
https://mail.python.org/mailman/listinfo/python-list
Re: zpifile.py error - no crc 32 attribute
" import zlib print(zlib.__file__)" When I don't have the zlib uploaded to my Python3.7 library, I have the following error: "Traceback (most recent call last): File "./testx.py", line 2, in import zlib ModuleNotFoundError: No module named 'zlib'" When I download the zlib 1.2.11 from http://www.zlib.net/, rename the "zlib-1.2.11" folder into "zlib" (after unpacking) and upload it into Python library, the result is: "# ./testx.py None " In the second case I still have the AttributeError with crc32. On 22 August 2018 at 23:09, Ashok Arora wrote: > Test this in the interpreter:- > > import zlib > zlib.__file__ > > It will return the location of zlib module. > > On 8/22/18, jacob m wrote: > > Hi, > > " Is there perhaps a different zlib on > > your path, hiding the real zlib?" - I'm unsure of that. > > > > "sudo apt-get install zlib1g-dev > > Reading package lists... Done > > Building dependency tree > > Reading state information... Done > > zlib1g-dev is already the newest version. > > 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded." > > Regards > > > > > > On 22 August 2018 at 13:12, jacob m wrote: > > > >> Hi guys, > >> I have a problem with zipfile and zlib module, and hope to get some > help. > >> > >> That's my error: > >> "import zipfile > >> File "/home/lib/python3.7/lib/python3.7/zipfile.py", line 19, in > >> > >> crc32 = zlib.crc32 > >> AttributeError: module 'zlib' has no attribute 'crc32' " > >> > >> I have no idea what to do with that :/ I use this version of zipfile: > >> https://github.com/python/cpython/blob/3.7/Lib/zipfile.py > >> > >> Somebody knows how to solve it? > >> Regards > >> > >> > > -- > > https://mail.python.org/mailman/listinfo/python-list > > > -- https://mail.python.org/mailman/listinfo/python-list
Re: zpifile.py error - no crc 32 attribute
Test this in the interpreter:- import zlib zlib.__file__ It will return the location of zlib module. On 8/22/18, jacob m wrote: > Hi, > " Is there perhaps a different zlib on > your path, hiding the real zlib?" - I'm unsure of that. > > "sudo apt-get install zlib1g-dev > Reading package lists... Done > Building dependency tree > Reading state information... Done > zlib1g-dev is already the newest version. > 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded." > Regards > > > On 22 August 2018 at 13:12, jacob m wrote: > >> Hi guys, >> I have a problem with zipfile and zlib module, and hope to get some help. >> >> That's my error: >> "import zipfile >> File "/home/lib/python3.7/lib/python3.7/zipfile.py", line 19, in >> >> crc32 = zlib.crc32 >> AttributeError: module 'zlib' has no attribute 'crc32' " >> >> I have no idea what to do with that :/ I use this version of zipfile: >> https://github.com/python/cpython/blob/3.7/Lib/zipfile.py >> >> Somebody knows how to solve it? >> Regards >> >> > -- > https://mail.python.org/mailman/listinfo/python-list > -- https://mail.python.org/mailman/listinfo/python-list
Re: zpifile.py error - no crc 32 attribute
On 08/23/2018 12:43 AM, jacob m wrote: " import zlib print(zlib.__file__)" When I don't have the zlib uploaded to my Python3.7 library, I have the following error: "Traceback (most recent call last): File "./testx.py", line 2, in import zlib ModuleNotFoundError: No module named 'zlib'" zlib is part of the standard library. It should have been there when you installed Python. When I download the zlib 1.2.11 from http://www.zlib.net/, rename the "zlib-1.2.11" folder into "zlib" (after unpacking) and upload it into Python library, the result is: Don't do that. * that's not a Python package. It has no business being in the Python path. * don't put things into the Python path willy-nilly. Let the canonical tools (i.e.: pip, setup.py files, etc.) take care of it. * DEFINITELY don't put your own stuff into the *standard* library location. Use site-packages/ for custom packages. Install Python again from scratch. If you can't import zlib and zipfile in a *clean* Python install, come back and tell us how you installed Python and what OS/distribution you're using. Then I'm sure we can help you figure out what went wrong. If you installed from source and you didn't have zlib headers installed at the time, I could imagine this happening... but I have no idea if Python would even build without zlib. -- Thomas "# ./testx.py None " In the second case I still have the AttributeError with crc32. On 22 August 2018 at 23:09, Ashok Arora wrote: Test this in the interpreter:- import zlib zlib.__file__ It will return the location of zlib module. On 8/22/18, jacob m wrote: Hi, " Is there perhaps a different zlib on your path, hiding the real zlib?" - I'm unsure of that. "sudo apt-get install zlib1g-dev Reading package lists... Done Building dependency tree Reading state information... Done zlib1g-dev is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded." Regards On 22 August 2018 at 13:12, jacob m wrote: Hi guys, I have a problem with zipfile and zlib module, and hope to get some help. That's my error: "import zipfile File "/home/lib/python3.7/lib/python3.7/zipfile.py", line 19, in crc32 = zlib.crc32 AttributeError: module 'zlib' has no attribute 'crc32' " I have no idea what to do with that :/ I use this version of zipfile: https://github.com/python/cpython/blob/3.7/Lib/zipfile.py Somebody knows how to solve it? Regards -- https://mail.python.org/mailman/listinfo/python-list -- https://mail.python.org/mailman/listinfo/python-list
Re: zpifile.py error - no crc 32 attribute
On 2018-08-22 23:43, jacob m wrote: " import zlib print(zlib.__file__)" When I don't have the zlib uploaded to my Python3.7 library, I have the following error: "Traceback (most recent call last): File "./testx.py", line 2, in import zlib ModuleNotFoundError: No module named 'zlib'" When I download the zlib 1.2.11 from http://www.zlib.net/, rename the "zlib-1.2.11" folder into "zlib" (after unpacking) and upload it into Python library, the result is: "# ./testx.py None " In the second case I still have the AttributeError with crc32. In the first case, without the downloaded zlip, can you import zipfile? If yes, try: zipfile.zlib From what I've seen, zlib is a built-in. On 22 August 2018 at 23:09, Ashok Arora wrote: Test this in the interpreter:- import zlib zlib.__file__ It will return the location of zlib module. On 8/22/18, jacob m wrote: > Hi, > " Is there perhaps a different zlib on > your path, hiding the real zlib?" - I'm unsure of that. > > "sudo apt-get install zlib1g-dev > Reading package lists... Done > Building dependency tree > Reading state information... Done > zlib1g-dev is already the newest version. > 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded." > Regards > > > On 22 August 2018 at 13:12, jacob m wrote: > >> Hi guys, >> I have a problem with zipfile and zlib module, and hope to get some help. >> >> That's my error: >> "import zipfile >> File "/home/lib/python3.7/lib/python3.7/zipfile.py", line 19, in >> >> crc32 = zlib.crc32 >> AttributeError: module 'zlib' has no attribute 'crc32' " >> >> I have no idea what to do with that :/ I use this version of zipfile: >> https://github.com/python/cpython/blob/3.7/Lib/zipfile.py >> >> Somebody knows how to solve it? >> Regards >> -- https://mail.python.org/mailman/listinfo/python-list
