Re: Caching: Access a local file, but ensure it is up-to-date from a remote URL
On Mon, Oct 13, 2014 at 5:36 PM, Ben Finney wrote: > So this is something similar to an HTTP object cache. Except where those > are usually URL-focussed with the local files a hidden implementation > detail, I want an API that focusses on the local files, with the remote > requests a hidden implementation detail. Potential issue: You may need some metadata storage as well as the actual files. Or can you just ignore the Varies header etc etc etc, and pretend that this URL represents a single blob of data no matter what? I'm also dubious about relying on FS timestamps for critical data, as it's very easy to bump the timestamp to current, which would make your program think that the contents are fresh; but if that's truly the only metadata needed, that might be safe to accept. One way you could possibly do this is to pick up a URL-based cache (even something stand-alone like Squid), and then create symlinks from your canonically-named local files to the implementation-detail storage space for the cache. Then you probe the URL and return its contents. That guarantees that you're playing nicely with the rules of HTTP (particularly if you have chained proxies, proxy authentication, etc, etc - if you're deploying this to arbitrary locations, that might be an issue), but at the expense of complexity. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: what is the easiest way to install multiple Python versions?
On Mon, Oct 13, 2014 at 1:31 PM, Rustom Mody wrote: > Hearing a bit about docker nowadays. > > Here's why its supposedly better than a VM: > https://www.docker.com/whatisdocker/ > > Downsides?? No idea! One obvious downside is that it doesn't allow guests to modify the OS at all. A VM gives you an entire OS, so you can use and manipulate anything. If you don't *need* all that flexibility, then a VM is paying an unnecessary cost, ergo Docker will have no downside. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: what is the easiest way to install multiple Python versions?
On Monday, October 13, 2014 1:24:27 PM UTC+5:30, Chris Angelico wrote: > On Mon, Oct 13, 2014 at 1:31 PM, Rustom Mody wrote: > > Hearing a bit about docker nowadays. > > Here's why its supposedly better than a VM: > > https://www.docker.com/whatisdocker/ > > Downsides?? No idea! > One obvious downside is that it doesn't allow guests to modify the OS > at all. A VM gives you an entire OS, so you can use and manipulate > anything. If you don't *need* all that flexibility, then a VM is > paying an unnecessary cost, ergo Docker will have no downside. Was talking of more pragmatic downsides eg "Does it really work?" :-) [Docker is still quite new] -- https://mail.python.org/mailman/listinfo/python-list
Re: Toggle
On Mon, 13 Oct 2014 05:43:10 +1100, Chris Angelico wrote: > On Mon, Oct 13, 2014 at 5:38 AM, Tony the Tiger > wrote: >>> colour = 'red' if colour == 'blue' else 'blue' >> >> I call that a subtle bug that most likely will jump up and bite your >> behind when you least expect it. > > More generally, I'd say that this is solving a (very) slightly different > problem: it's providing a "toggle with default" feature, > where the part after the else is the default. If you don't want a > default, that's a bug. I've known times when that default makes life a > lot easier, in which case it'd be a feature. > > ChrisA if the value of colour is being set by user input & an incorrect value can be set the the error is in not validating user input and more complex solutions are definitely req. If the value is being set within the program itself and colour gets set to an incorrect value the bug lies elsewhere in the program. this looks like a simple requirement to alternate the colour of a GUI element so it is unlikely that incorrect values will be set. sometimes it is easy to get carried away & overcomplicate a simple task, I tend to follow the "KISS" principle wherever possible -- 40 isn't old. If you're a tree. -- https://mail.python.org/mailman/listinfo/python-list
Re: while loop - multiple condition
On 10/12/2014 07:08 PM, Shiva wrote:
while ans.lower() != 'yes' or ans.lower()[0] != 'y':
ans = input('Do you like python?')
I personally consider double negations less intuitive than following:
while not( ans.lower() == 'yes' and ans.lower()[0] == 'y' ):
Reading this line yoy would have noticed as wellm that what you really
wanted would have been:
while not( ans.lower() == 'yes' or ans.lower()[0] == 'y' ):
I would write the coder differently.
With your code you have to pre-initialze the variable ans.
I personally consider it also more 'intuitive' / easier to understand if
I can see the break conditiion. to many nots / != / negations can be
confusing as you noticed yourself.
Taking into account the Steven's suggestion about using the 'in'
expression it could be:
while True:
ans = input('Do you like python?')
if ans.lower() in ('yes', 'y'):
break
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windows 7 pysqlite build error
I am getting this error trying to use a python27 pip install of stuff which ends up requiring pysqlite>=2.6.3,<2.7 building 'pysqlite2._sqlite' extension creating build\temp.win-amd64-2.7 creating build\temp.win-amd64-2.7\Release creating build\temp.win-amd64-2.7\Release\src c:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\BIN\amd64\cl.exe /c /nologo /Ox /MD /W3 /GS- /DNDEBUG -DMODULE_NAM E=\"pysqlite2.dbapi2\" -DSQLITE_OMIT_LOAD_EXTENSION=1 -IC:\python27\include -IC:\Users\rptlab\tmp\tenv\PC /Tcsrc/ module.c /Fobuild\temp.win-amd64-2.7\Release\src/module.obj module.c c:\users\rptlab\tmp\tmcallister\build\pysqlite\src\connection.h(33) : fatal error C1083: Cannot open include file: 'sqli te3.h': No such file or directory error: command 'c:\\Program Files (x86)\\Microsoft Visual Studio 9.0\\VC\\BIN\\amd64\\cl.exe' failed with exit status 2 Cleaning up... I do have the various compilers installed and other extensions are building OK, so is this an error in pysqlite or in my general setup? The include path looks like it might relate to Python builds. I suppose it's feasible that pyqslite builds need to be installed specially. I don't remember this happening on my old win32 XP system, but that died and I now am forced to use 64bit win7. -- Robin Becker -- https://mail.python.org/mailman/listinfo/python-list
Re: TypeError: 'kwarg' is an invalid keyword argument for this function
Ian Kelly Wrote in message:
> On Sun, Oct 12, 2014 at 6:55 AM, roro codeath wrote:
>> How to implement it in my class?
>>
>> class Str(str):
>> def __init__(self, *args, **kwargs):
>> pass
>>
>> Str('smth', kwarg='a')
>
> The error is coming from the __new__ method. Because str is an
> immutable type, you should override the __new__ method, not __init__.
> Example:
>
> class Str(str):
> def __new__(cls, *args, **kwargs):
> return super().__new__(cls, args[0])
>
Str('smth', kwarg='a')
> 'smth'
>
It would also help to spell it the same. In the OP's
implementation, he defined kwargs, and tried to use it as
kwarg.
--
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Re: TypeError: 'kwarg' is an invalid keyword argument for this function
Dave Angel wrote:
> Ian Kelly Wrote in
> message:
>> On Sun, Oct 12, 2014 at 6:55 AM, roro codeath
>> wrote:
>>> How to implement it in my class?
>>>
>>> class Str(str):
>>> def __init__(self, *args, **kwargs):
>>> pass
>>>
>>> Str('smth', kwarg='a')
>>
>> The error is coming from the __new__ method. Because str is an
>> immutable type, you should override the __new__ method, not __init__.
>> Example:
>>
>> class Str(str):
>> def __new__(cls, *args, **kwargs):
>> return super().__new__(cls, args[0])
>>
> Str('smth', kwarg='a')
>> 'smth'
>>
>
> It would also help to spell it the same. In the OP's
> implementation, he defined kwargs, and tried to use it as
> kwarg.
That is consistent as should become clear when using something completely
different:
>>> class Str(str):
... def __init__(self, *args, **kwargs): pass
...
>>> Str("smth", alpha="beta")
Traceback (most recent call last):
File "", line 1, in
TypeError: 'alpha' is an invalid keyword argument for this function
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Jython or Pyton issue-- Kindly Help me....
Dear All, How to write a program for reading or parsing the XML file in Sub root Wise. For ex: Below XMl, I want to read/ parse first country details and here also two year tag values are there.. Here I need to read/parse first year value only measn '2008' Only..After that I need to read second country details. Please help me .. i am struggling to get this solution.. 1 2008 2009> 141100 4 2011 59900 68 2011 13600 -- https://mail.python.org/mailman/listinfo/python-list
Re: while loop - multiple condition
On Mon, Oct 13, 2014 at 7:31 PM, Gelonida N wrote:
> Taking into account the Steven's suggestion about using the 'in' expression
> it could be:
>
>
> while True:
> ans = input('Do you like python?')
> if ans.lower() in ('yes', 'y'):
> break
Or, even simpler: Use an active condition.
while input('Do you like python?') not in ('yes', 'y'): pass
ChrisA
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Re: while loop - multiple condition
Chris Angelico :
> Or, even simpler: Use an active condition.
>
> while input('Do you like python?') not in ('yes', 'y'): pass
Instead of the traditional "pull" technology, you could take advantage
of the state-of-the-art "push" approach:
print("You must love python -- everybody does!")
Marko
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Re: while loop - multiple condition
On Mon, Oct 13, 2014 at 6:59 AM, Chris Angelico wrote:
> while input('Do you like python?') not in ('yes', 'y'): pass
Unfortunately, you probably have to account for people who SHOUT:
while input('Do you like python?').lower() not in ('yes', 'y'): pass
Skip
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Re: while loop - multiple condition
On Mon, Oct 13, 2014 at 11:10 PM, Skip Montanaro
wrote:
> On Mon, Oct 13, 2014 at 6:59 AM, Chris Angelico wrote:
>>
>> while input('Do you like python?') not in ('yes', 'y'): pass
>
>
> Unfortunately, you probably have to account for people who SHOUT:
>
> while input('Do you like python?').lower() not in ('yes', 'y'): pass
>
>
Welcome to collaborative editing. I make a change and introduce a bug.
Fortunately, someone else can, just like that, fix that bug. Thanks!
:)
ChrisA
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Re: while loop - multiple condition
On Mon, Oct 13, 2014 at 11:09 PM, Marko Rauhamaa wrote:
> Chris Angelico :
>
>> Or, even simpler: Use an active condition.
>>
>> while input('Do you like python?') not in ('yes', 'y'): pass
>
> Instead of the traditional "pull" technology, you could take advantage
> of the state-of-the-art "push" approach:
>
>print("You must love python -- everybody does!")
Nay, there is love in excess. I thank heaven there are many pythons in
England; but if thou lovest them all, I withdraw my thanks!
-- Colonel Fairfax
ChrisA
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Re: what is the easiest way to install multiple Python versions?
On Mon, Oct 13, 2014 at 7:00 PM, Rustom Mody wrote: > On Monday, October 13, 2014 1:24:27 PM UTC+5:30, Chris Angelico wrote: >> On Mon, Oct 13, 2014 at 1:31 PM, Rustom Mody wrote: >> > Hearing a bit about docker nowadays. >> > Here's why its supposedly better than a VM: >> > https://www.docker.com/whatisdocker/ >> > Downsides?? No idea! > >> One obvious downside is that it doesn't allow guests to modify the OS >> at all. A VM gives you an entire OS, so you can use and manipulate >> anything. If you don't *need* all that flexibility, then a VM is >> paying an unnecessary cost, ergo Docker will have no downside. > > Was talking of more pragmatic downsides eg "Does it really work?" :-) > [Docker is still quite new] Ah, I can't help you there. I've never used Docker. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: what is the easiest way to install multiple Python versions?
On 10/12/14 9:33 AM, Albert-Jan Roskam wrote: Hi, (sorry for cross-posting) A few days ago I needed to check whether some Python code ran with Python 2.6. What is the easiest way to install another Python version along side the default Python version? My own computer is Debian Linux 64 bit, but a platform-independent solution would be best. Possible solutions that I am aware of -make altinstall *). This is what I tried (see below), but not all modules could be built. I gave up because I was in a hurry -Pythonbrew. This project is dead -Deadsnakes -Anaconda -Tox? I only know this is as a cross-version/implementation test runner -Vagrant. This is what I eventually did, and this was very simple. I ran Ubuntu 10.0.4 LTS, which uses Python 2.6, and used Vagrant SSH to run and check my code in Python 2.6 (and I replaced a dict comprehension with a list comprehension, for example) - ... What is the recommended way? I don't expect/hope that I'd ever need something lower than Python 2.5 I use pythonz: http://saghul.github.io/pythonz/ It lets me specify not just the version I want, but the implementation I want: I can install CPython 2.6.1, PyPy 2.0.2, and Jython 2.5.3 all the same way. -- Ned Batchelder, http://nedbatchelder.com -- https://mail.python.org/mailman/listinfo/python-list
Re: Jython or Pyton issue-- Kindly Help me....
On Mon, Oct 13, 2014 at 5:39 AM, Venugopal Reddy wrote: > Dear All, > > How to write a program for reading or parsing the XML file in Sub root Wise. I don't know what "Sub root Wise" is. You can find an overview of Python's XML parsing interfaces at https://docs.python.org/2/library/xml.html. I would recommend using the ElementTree API unless you have a specific reason to use something else. -- https://mail.python.org/mailman/listinfo/python-list
Re: while loop - multiple condition
On Mon, 13 Oct 2014 09:56:02 +1100 Steven D'Aprano wrote: > > When you have multiple clauses in the condition, it's easier to reason about > them if you write the clauses as positive statements rather than negative > statements, that is, "something is true" rather than "something is not > true", and then use `not` to reverse it if you want to loop *until* the > overall condition is true. > I was just explaining this concept to a young pup the other day. De Morgan's lets you say that (not (p and q)) == ((not p) or (not q)), but the positive logic flavor is substantially less error-prone. People are fundamentally not as good at thinking about inverted logic. -- Rob Gaddi, Highland Technology -- www.highlandtechnology.com Email address domain is currently out of order. See above to fix. -- https://mail.python.org/mailman/listinfo/python-list
Re: while loop - multiple condition
On Monday, October 13, 2014 9:43:03 PM UTC+5:30, Rob Gaddi wrote: > On Mon, 13 Oct 2014 09:56:02 +1100 > Steven D'Aprano wrote: > > When you have multiple clauses in the condition, it's easier to reason about > > them if you write the clauses as positive statements rather than negative > > statements, that is, "something is true" rather than "something is not > > true", and then use `not` to reverse it if you want to loop *until* the > > overall condition is true. > I was just explaining this concept to a young pup the other day. De > Morgan's lets you say that (not (p and q)) == ((not p) or (not q)), but > the positive logic flavor is substantially less error-prone. People > are fundamentally not as good at thinking about inverted logic. Curious: Which of - (not (p and q)) - ((not p) or (not q)) is more positive (less negative)?? -- https://mail.python.org/mailman/listinfo/python-list
Re: while loop - multiple condition
On Mon, 13 Oct 2014 09:26:57 -0700 (PDT) Rustom Mody wrote: > On Monday, October 13, 2014 9:43:03 PM UTC+5:30, Rob Gaddi wrote: > > On Mon, 13 Oct 2014 09:56:02 +1100 > > Steven D'Aprano wrote: > > > When you have multiple clauses in the condition, it's easier to reason > > > about > > > them if you write the clauses as positive statements rather than negative > > > statements, that is, "something is true" rather than "something is not > > > true", and then use `not` to reverse it if you want to loop *until* the > > > overall condition is true. > > > I was just explaining this concept to a young pup the other day. De > > Morgan's lets you say that (not (p and q)) == ((not p) or (not q)), but > > the positive logic flavor is substantially less error-prone. People > > are fundamentally not as good at thinking about inverted logic. > > Curious: Which of > > - (not (p and q)) > - ((not p) or (not q)) > > is more positive (less negative)?? The first is asking you to compare positive conditions (p and q) and negate the entire thing (NAND). The second asks you to think about the combination of two different "not true" pieces of logic (OR of two inverted inputs). The first is pretty straightforward, and I usually see people get it right. The second gets screwed up as often as not. And of course, any combination of ands and ors should be broken into multiple statements with a descriptive variable name in the middle or all hope is lost. -- Rob Gaddi, Highland Technology -- www.highlandtechnology.com Email address domain is currently out of order. See above to fix. -- https://mail.python.org/mailman/listinfo/python-list
Re: while loop - multiple condition
On Monday, October 13, 2014 10:13:20 PM UTC+5:30, Rob Gaddi wrote: > On Mon, 13 Oct 2014 09:26:57 -0700 (PDT) > Rustom Mody wrote: > > On Monday, October 13, 2014 9:43:03 PM UTC+5:30, Rob Gaddi wrote: > > > On Mon, 13 Oct 2014 09:56:02 +1100 > > > Steven D'Aprano wrote: > > > > When you have multiple clauses in the condition, it's easier to reason > > > > about > > > > them if you write the clauses as positive statements rather than > > > > negative > > > > statements, that is, "something is true" rather than "something is not > > > > true", and then use `not` to reverse it if you want to loop *until* the > > > > overall condition is true. > > > I was just explaining this concept to a young pup the other day. De > > > Morgan's lets you say that (not (p and q)) == ((not p) or (not q)), but > > > the positive logic flavor is substantially less error-prone. People > > > are fundamentally not as good at thinking about inverted logic. > > Curious: Which of > > - (not (p and q)) > > - ((not p) or (not q)) > > is more positive (less negative)?? > The first is asking you to compare positive conditions (p and q) and > negate the entire thing (NAND). The second asks you to think about > the combination of two different "not true" pieces of logic > (OR of two inverted inputs). The first is pretty straightforward, and > I usually see people get it right. The second gets screwed up as often > as not. > And of course, any combination of ands and ors should be broken into > multiple statements with a descriptive variable name in the middle or > all hope is lost. Yeah I guess 2 nots is one more than one! However (to my eyes) while i < N and a[i] != X: looks less negative than while not (i==N or a[i] == X): [Of course i < N is not identical to i != N ] -- https://mail.python.org/mailman/listinfo/python-list
How to select every other line from a text file?
Hi, I have a text file. Now it is required to select every other line of that text to generate a new text file. I have read through Python grammar, but still lack the idea at the beginning of the task. Could you tell me some methods to get this? Thanks, -- https://mail.python.org/mailman/listinfo/python-list
Re: How to select every other line from a text file?
On Tue, Oct 14, 2014 at 4:38 AM, Rff wrote: > I have a text file. Now it is required to select every other line of that > text to > generate a new text file. I have read through Python grammar, but still lack > the > idea at the beginning of the task. Could you tell me some methods to get > this? > There are a few ways of doing this. I'm guessing this is probably a homework assignment, so I won't give you the code as-is, but here are a few ideas: 1) Iterate over the file (line by line), alternating between writing the line out and not writing the line out. 2) Read the file into a list of lines, then slice the list with a step of 2, and write those lines out. 3) Iterate over the file, but also consume an extra line at the top or bottom of the loop. 4) Read the entire file into a string, then abuse regular expressions violently until they do what you want. And there are other ways, too. Show us some code and we can help you with it; but at the moment, this is fairly open-ended. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: How to select every other line from a text file?
In <3be64ca8-d2e7-493a-b4f3-ef114f581...@googlegroups.com> Rff writes: > Hi, > I have a text file. Now it is required to select every other line of that > text to generate a new text file. I have read through Python grammar, but > still lack the idea at the beginning of the task. Could you tell me some > methods to get this? Initialize a counter variable to zero. (Or one, depending if you want to select odd or even lines.) Each time you read a line from the file, add one to the counter. If the counter is odd, process the line; otherwise use the 'continue' statement to start the loop over and read another line. -- John Gordon Imagine what it must be like for a real medical doctor to gor...@panix.comwatch 'House', or a real serial killer to watch 'Dexter'. -- https://mail.python.org/mailman/listinfo/python-list
Re: How to select every other line from a text file?
On 10/13/2014 10:38 AM, Rff wrote: Hi, I have a text file. Now it is required to select every other line of that text to generate a new text file. I have read through Python grammar, but still lack the idea at the beginning of the task. Could you tell me some methods to get this? Thanks, Read in your lines, keeping a counter as you go. "Select" those lines whose counter is even (or odd -- you didn't say which you wanted). So now some questions for you: * Do you know how to open a file and read in all the lines? * Do you know how to count as you do so? * Do you know how to test for evenness? (Use count%2 will be zero for even count values.) * Do you know how to write lines to an output file? Gary Herron -- https://mail.python.org/mailman/listinfo/python-list
Re: How to select every other line from a text file?
On 13/10/2014 18:48, John Gordon wrote: In <3be64ca8-d2e7-493a-b4f3-ef114f581...@googlegroups.com> Rff writes: Hi, I have a text file. Now it is required to select every other line of that text to generate a new text file. I have read through Python grammar, but still lack the idea at the beginning of the task. Could you tell me some methods to get this? Initialize a counter variable to zero. (Or one, depending if you want to select odd or even lines.) Each time you read a line from the file, add one to the counter. If the counter is odd, process the line; otherwise use the 'continue' statement to start the loop over and read another line. Why bother to initialise a counter when you can get the enumerate function to do all the work for you? -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence -- https://mail.python.org/mailman/listinfo/python-list
Re: How to select every other line from a text file?
On 10/13/2014 11:02 AM, Mark Lawrence wrote: Why bother to initialise a counter when you can get the enumerate function to do all the work for you? I see it as a question of addressing the audience. Emile -- https://mail.python.org/mailman/listinfo/python-list
scipy errors and gfortran
Trying to get scipy 0.14 running on python 3.4.1 on SLES 11 SP2 LINUX system.
Scipy seemed to compile fine using the command "python setup.py install" but
when I try the scipy.test("full"), I get errors regarding gfortran. I am using
GCC(gfortran) version 4.9.1.
The error states that /usr/lib/libgfortran.so.3: version 'gfortran_1.4' was not
found (required by). Google tells me that this is the name of the symbol
node whatever that means.
What do I need to do to fix these errors? Please help.
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Re: How to select every other line from a text file?
On Mon, Oct 13, 2014 at 2:11 PM, emile wrote: > On 10/13/2014 11:02 AM, Mark Lawrence wrote: > >> Why bother to initialise a counter when you can get the enumerate >> function to do all the work for you? > > > I see it as a question of addressing the audience. > > Emile I don't agree with the idea of using a counter. Its not pythonic, and I'm assuming the OP is just starting to learn python. Not apropos to the OP, but what came up in my mind was to write a generator function that returns every other line. This would separate the reading from the writing code. > > > > -- > https://mail.python.org/mailman/listinfo/python-list -- Joel Goldstick http://joelgoldstick.com -- https://mail.python.org/mailman/listinfo/python-list
Re: How to select every other line from a text file?
On 2014-10-13, Chris Angelico wrote:
> On Tue, Oct 14, 2014 at 4:38 AM, Rff wrote:
>> I have a text file. Now it is required to select every other line of that
>> text to
>> generate a new text file. I have read through Python grammar, but still
>> lack the
>> idea at the beginning of the task. Could you tell me some methods to get
>> this?
>>
>
> There are a few ways of doing this. I'm guessing this is probably a
> homework assignment, so I won't give you the code as-is, but here are
> a few ideas:
>
> 1) Iterate over the file (line by line), alternating between writing
>the line out and not writing the line out.
>
> 2) Read the file into a list of lines, then slice the list with a step
>of 2, and write those lines out.
>
> 3) Iterate over the file, but also consume an extra line at the top or
>bottom of the loop.
>
> 4) Read the entire file into a string, then abuse regular expressions
>violently until they do what you want.
I'd vote for #3. Or write a generator that does something similar
when given a parameter object that implements readline().
Of course, the _real_ answer is:
os.system("sed -n 'g;n;p' '%s'" % filename)
;)
--
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at Packard from you last March
gmail.comin Cairo?
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Re: How to select every other line from a text file?
On 2014-10-13 10:38, Rff wrote:
> Hi,
> I have a text file. Now it is required to select every other line
> of that text to generate a new text file. I have read through
> Python grammar, but still lack the idea at the beginning of the
> task. Could you tell me some methods to get this?
You could force a re-read from the file each line:
with open("x.txt") as f:
for line in f:
do_something(line)
next(f) # discard/consume the next line
Or, if you have it read into memory already, you could use slicing
with a stride of 2:
with open("x.txt") as f:
data = f.readlines()
interesting = data[::2] # start with the 1st line
# interesting = data[1::2] # start with the 2nd line
Or, if the file was large and you didn't want to have it all in
memory at the same time, you could use itertools.islice()
from itertools import islice
with open("x.txt") as f:
interesting = islice(f, 0, None, 2) # start with 1st line
#interesting = islice(f, 1, None, 2) # start with 2nd line
Note that in the last one, you get an iterator back, so you'd have to
either turn it into a list or iterate over it.
-tkc
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Re: How to select every other line from a text file?
On 2014-10-13 14:45, Joel Goldstick wrote: > Not apropos to the OP, but what came up in my mind was to write a > generator function that returns every other line. This would > separate the reading from the writing code. You mean like offset = 0 # or 1 if you prefer for line in itertools.islice(source_iter, offset, None, 2): do_something(line) ? -tkc -- https://mail.python.org/mailman/listinfo/python-list
Re: How to select every other line from a text file?
On 10/13/2014 12:12 PM, Tim Chase wrote: You mean like offset = 0 # or 1 if you prefer for line in itertools.islice(source_iter, offset, None, 2): do_something(line) I certainly did. Learning the python standard library is different from learning python and each in its own time. Emile -- https://mail.python.org/mailman/listinfo/python-list
Re: windows 7 pysqlite build error
On 10/13/2014 4:31 PM, Dennis Lee Bieber wrote: On Mon, 13 Oct 2014 10:49:27 +0100, Robin Becker declaimed the following: c:\users\rptlab\tmp\tmcallister\build\pysqlite\src\connection.h(33) : fatal error C1083: Cannot open include file: 'sqli te3.h': No such file or directory Did \n get stuck in the name of the file in connection.h, or is that purely an artifact of the error reporting? error: command 'c:\\Program Files (x86)\\Microsoft Visual Studio 9.0\\VC\\BIN\\amd64\\cl.exe' failed with exit status 2 I do have the various compilers installed and other extensions are building OK, so is this an error in pysqlite or in my general setup? The include path looks like it might relate to Python builds. I suppose it's feasible that pyqslite builds need to be installed specially. I don't remember this happening on my old win32 XP system, but that died and I now am forced to use 64bit win7. Off hand, you don't have the SQLite3 /development package/. PySQLite is just an adapter to the sqlite3 DLL; the sqlite3.h file would be part of the source code for sqlite3, not part of pysqlite itself. -- Terry Jan Reedy -- https://mail.python.org/mailman/listinfo/python-list
Re: Flask and Django
On 10/10/2014 04:22 PM, Juan Christian wrote: > Maybe that's because I feel the Django doc a bit confuse, I tried reading > (and practicing!) tutorials, official doc, books, and so on, but I can't > quite understand the whole thing. > > Is Flask really underestimated? Can you guys mention "big name" companies > or people using it? Does it have real value in real world business? Nothing wrong with using Flask, especially for a personal project, or even something commercial. That said, Django is pretty easy to get started with. I have done very little web development ever, and I can fairly easily get going with Django. The tutorials are quite good. If you have problems with them, you can get help on the django mailing lists and forums, I am sure. Django does seem to get a lot of attention. It's getting to be a huge framework, with lots of bells and whistles, but I'm pretty sure you can still use as much or as little of it as you need, and even discard parts of it, such as the native Django database persistance API, and use, say, sqalchemy. -- https://mail.python.org/mailman/listinfo/python-list
Re: while loop - multiple condition
On 10/13/2014 11:12 AM, Rustom Mody wrote: > On Monday, October 13, 2014 10:13:20 PM UTC+5:30, Rob Gaddi wrote: >> On Mon, 13 Oct 2014 09:26:57 -0700 (PDT) >> Rustom Mody wrote: > >>> On Monday, October 13, 2014 9:43:03 PM UTC+5:30, Rob Gaddi wrote: On Mon, 13 Oct 2014 09:56:02 +1100 Steven D'Aprano wrote: > When you have multiple clauses in the condition, it's easier to reason > about > them if you write the clauses as positive statements rather than negative > statements, that is, "something is true" rather than "something is not > true", and then use `not` to reverse it if you want to loop *until* the > overall condition is true. I was just explaining this concept to a young pup the other day. De Morgan's lets you say that (not (p and q)) == ((not p) or (not q)), but the positive logic flavor is substantially less error-prone. People are fundamentally not as good at thinking about inverted logic. >>> Curious: Which of >>> - (not (p and q)) >>> - ((not p) or (not q)) >>> is more positive (less negative)?? > >> The first is asking you to compare positive conditions (p and q) and >> negate the entire thing (NAND). The second asks you to think about >> the combination of two different "not true" pieces of logic >> (OR of two inverted inputs). The first is pretty straightforward, and >> I usually see people get it right. The second gets screwed up as often >> as not. > >> And of course, any combination of ands and ors should be broken into >> multiple statements with a descriptive variable name in the middle or >> all hope is lost. > > Yeah I guess 2 nots is one more than one! > > However (to my eyes) > while i < N and a[i] != X: > > looks less negative than > > while not (i==N or a[i] == X): > > [Of course i < N is not identical to i != N ] Right it should have been not (i >= N or a[i] == X) to be equivalent. In assembler it's often best to reverse the condition and then use the opposite jump mnemonic. IE, if the test is to see if a number not zero, use the jump if zero command instead. Often it reduces the number of jumps required and eliminates the need to jump over the body of the "if" block. if a != 0 then jump to bigger jump to end bigger: blah blah end: vs if a == 0 then jump to end blah blah end: -- https://mail.python.org/mailman/listinfo/python-list
Re: How to select every other line from a text file?
On Mon, 13 Oct 2014 10:38:48 -0700, Rff wrote: > I have a text file. Now it is required to select every other line of > that text to > generate a new text file. I have read through Python grammar, but still > lack the idea at the beginning of the task. Could you tell me some > methods to get this? So this could be written as an algorithm something like: 1/ open the input file 2/ open the output file 3/ while there are lines to read from the input file 3/1/ read a line from the input file 3/2/ if I should output this line 3/2/1/ write line to output file 4/ close the input file 5/ close the output file Or in several other ways, and once you have an algorithm, you can start coding it (or implementing it in the programming language of your choice, whichever form of words best pleases your perfesser). -- Denis McMahon, denismfmcma...@gmail.com -- https://mail.python.org/mailman/listinfo/python-list
Re: How to select every other line from a text file?
On Mon, Oct 13, 2014 at 10:38 AM, Rff wrote: > Hi, > I have a text file. Now it is required to select every other line of that > text to > generate a new text file. I have read through Python grammar, but still lack > the > idea at the beginning of the task. Could you tell me some methods to get > this? Perhaps something like: http://stromberg.dnsalias.org/svn/every-nth/trunk It uses zip and itertools.cycle. It's CPython 3.x though - if you need 2.x, you'd probably use xrange instead of range, and izip instead of zip. -- https://mail.python.org/mailman/listinfo/python-list
Need help in pulling SQL query out of log file...
Hi,
I have a log file which has lot of information like..SQL query.. number of
records read...records loaded etc..
My requirement is i would like to read the SQL query completly and write it to
another txt file.. also the log file may not be always same so can not make
static choices...
my logfile is like below :
*LOg file starts**
Fri Aug 08 16:00:04 2014 : WRITER_1_*_1> WRT_8005 Writer run started.
Fri Aug 08 16:00:04 2014 : READER_1_2_1> BLKR_16007 Reader run started.
Fri Aug 08 16:00:04 2014 : WRITER_1_*_1> WRT_8158
*START LOAD SESSION*
Load Start Time: Fri Aug 08 16:00:04 2014
Target tables:
EIS_REQUEST_LOG_26MAYBKP
T_delta_parm_file
Fri Aug 08 16:00:04 2014 : READER_1_2_1> RR_4010 SQ instance
[SQ_Shortcut_to_EIS_REQUEST_LOG] SQL Query [SELECT
EIS_REQUEST_LOG_26MAYBKP.RqstId, EIS_REQUEST_LOG_26MAYBKP.RQSTLoadStatCd FROM
EIS_REQUEST_LOG_26MAYBKP]
Fri Aug 08 16:00:04 2014 : READER_1_2_1> RR_4049 RR_4049 SQL Query issued to
database : (Fri Aug 08 16:00:04 2014)
Fri Aug 08 16:00:04 2014 : READER_1_2_1> RR_4035 SQL Error [
FnName: Prepare -- [Teradata][ODBC Teradata Driver][Teradata Database] Object
'EIS_REQUEST_LOG_26MAYBKP' does not exist. ].
Fri Aug 08 16:00:04 2014 : READER_1_2_1> BLKR_16004 ERROR: Prepare failed.
Fri Aug 08 16:00:04 2014 : READER_1_1_1> RR_4029 SQ Instance [SQ_RSTS_Tables]
User specified SQL Query [--- Approved By ICC Team---
---SELECT A.LOGSYS ,
---D."/BIC/NIGNRCSYS" ,
---B.ODSNAME ,
---C.ODSNAME_TECH ,
---C.PARTNO ,
---C.REQUEST ,
---E.SID
---FROM
---sapbzd."RSISOSMAP" A,
---sapbzd."RSTSODS" B,
---sapbzd."RSTSODSPART" C,
---sapbzd."/BIC/PNIGNRCSYS" D,
---sapbzd."/BI0/SREQUID" E,
---sapbzd."RSMONMESS"F
---WHERE A.OLTPSOURCE =
('ZNK_SHP_DDLN_CREATE_BE','ZNK_KNVP2_BD','ZNK_ZVBW_RTN_ORD_ITM_BN','2LIS_02_SCL_BE','ZNK_FX_CRCY_HIS_BE','ZNK_PO_FX_CALC_LOG_BD','2LIS_12_VCHDR_BE','2LIS_02_HDR_BN','ZNK_SHP_DDLN_CHANGE_BD','1_CO_PAGL11000N1_BE','0CUSTOMER_ATTR_BE','2LIS_08TRTLP_BD','2LIS_02_SCN_BD','2LIS_02_HDR_BD','2LIS_13_VDITM_BE','0CO_OM_CCA_9_BE','ZNK_SO_BDSI_OPNDMD_BE','2LIS_11_VAHDR_BE','ZNK_ZVBW_MBEW_BE','2LIS_13_VDHDR_BN','ZNK_SHP_DDLN_CHANGE_BE','NK_ADDR_NUMBR_BN','0CUSTOMER_TEXT_BE','6DB_J_3ABD_DELTA_AFFL_AD','0MAT_PLANT_ATTR_BE','ZNK_BDCPV_BD','1_CO_PAGL11000N1_BD','2LIS_11_VASTI_BD','ZNK_ZVBW_MSKU_BE','ZNK_SHP_DDLN_CREATE_BD','0SCEM_1_BC','2LIS_11_VAHDR_BD','2LIS_11_VASCL_BD','0MATERIAL_TEXT_BE','0MATERIAL_ATTR_BE','ZNK_BDCPV_BE','2LIS_02_ITM_BN','2LIS_11_VASCL_BE','2LIS_11_VAITM_BN','NK_ADDR_NUMBR_BE','2LIS_08TRTK_BE','ZNK_SD_LIKPPS_BN','2LIS_03_BF_BE','ZNK_SO_BDBS_ALLOC_BD','ZNK_TD_3AVASSO_BN','0EC_PCA_3_BD','ZNK_TD_3AVAP_BE','2LIS_11_VAITM_BE','0CUST_SALES_ATTR_BN','0EC_PCA_3_
BE','2LIS_13_VDITM_BN','2LIS_11_VASTH_BD','2LIS_13_VDITM_BD','0CUST_SALES_ATTR_BD','ZNK_TD_3AVASSO_BD','2LIS_02_SCN_BE','2LIS_08TRTS_BD','0CUSTOMER_ATTR_BN','ZNK_TD_3AVASSO_BE','ZNK_ZVBW_MSLB_BE','ZNK_TD_3AVAP_BD','0CUSTOMER_TEXT_BN','6DB_J_3ABD_DELTA_US_AD','0CUSTOMER_TEXT_BD','2LIS_11_VAHDR_BN','ZNK_SO_BDBS_ALLOC_BN','0GL_ACCOUNT_TEXT_BE','0GL_ACCOUNT_TEXT_BD','2LIS_11_VAITM_BD','ZNK_TD_3AVATL_BE','ZNK_SO_BDBS_ALLOC_BE','ZNK_EBAN_BE','ZNK_SO_BDSI_OPNDMD_BN','ZNK_SD_LIKPPS_BD','ZNK_ZVBW_RTN_ORD_ITM_BE','2LIS_08TRTS_BN','2LIS_02_HDR_BE','ZNK_TD_3AVATL_BD','ZNK_VBPA_BE','ZNK_FX_CRCY_HIS_BD','2LIS_13_VDHDR_BE','NK_ADDR_NUMBR_BD','2LIS_12_VCITM_BD','2LIS_08TRTK_BD','2LIS_11_VASCL_BN','ZNK_ZVBW_MCHB_BE','6DB_J_3ABD_SCL_DELTA_AP_AE','ZNK_SO_BDSI_OPNDMD_BD','ZNK_KNVP2_BE','0MAT_SALES_ATTR_BE','ZNK_TD_3AVAP_BN','2LIS_13_VDHDR_BD','0GL_ACCOUNT_ATTR_BD','2LIS_02_SCL_BD','ZNK_VBPA_BD','2LIS_02_ITM_BD','ZNK_TD_3AVATL_BN','ZNK_ZVBW_RTN_ORD_ITM_BD','ZNK_PO_FX_CALC_LOG_BE','6DB_J_3ABD_DELTA_EMEA_
AD','0GL_ACCOUNT_ATTR_BE','2LIS_03_BF_BD','2!
LIS_11_V
ASTI_BE','0CO_OM_CCA_9_BD','0CUST_SALES_ATTR_BE','2LIS_12_VCITM_BE','0CUSTOMER_ATTR_BD','2LIS_02_ITM_BE','2LIS_08TRTLP_BE','2LIS_12_VCHDR_BD','ZNK_EBAN_BD','2LIS_08TRTS_BE','2LIS_02_SCL_BN','2LIS_11_VASTH_BE','ZNK_SD_LIKPPS_BE')
---AND A.LOGSYS = D."/BIC/NKLOGSYST"
---AND A.OBJVERS = 'A'
---AND A.TRANSTRU = B.ODSNAME
---AND B.DATETO = 0101
---AND B.OBJSTAT = 'ACT'
---AND B.ODSNAME_TECH = C.ODSNAME_TECH
---AND C.DELFLAG <> 'X'
---AND D."/BIC/NIGNRCSYS" = ('R3_PRA','R3_PRD','R3_PRF','EM_EMP')
---AND D.OBJVERS = 'A'
---AND E.REQUID = C.REQUEST
---AND F.RNR = C.REQUEST
---AND F.MSGNO = '344'
---AND F.AUFRUFER = '09'---
SELECT A.LOGSYS ,
D."/BIC/NIGNRCSYS" ,
B.ODSNAME ,
C.ODSNAME_TECH ,
C.PARTNO ,
C.REQUEST ,
E.SID
FROM
sapbzd."RSISOSMAP" A,
sapbzd."RSTSODS" B,
sapbzd."RSTSODSPART" C,
sapbzd."/BIC/PNIGNRCSYS" D,
sapbzd."/BI0/SREQUID" E,
sapbzd."RSMONMESS"F
WHERE
A.OLTPSOURCE in
('ZNK_SHP_DDLN_CREATE_BE','ZNK_KNVP2_BD','ZNK_ZVBW_RTN_ORD_ITM_BN','2LIS_02_SCL_BE','ZNK_FX_CRCY_HIS_BE','ZNK_PO_FX_CALC_LOG_BD','2LIS_12_VCHDR_BE','2LIS_02_HDR_BN','ZNK_SHP_DDLN_CHANGE_BD','1_CO_PAGL11000N1_BE','0CUSTOMER_ATTR_BE','2LIS_08TRTLP_BD','2LIS_02_SCN_BD','2LIS_02_HDR_BD','2LIS_13_VDITM
Re: How to install and run a script?
On 10/12/2014 08:05 PM, ryguy7272 wrote: > Ah!!! I didn't know I needed to run it from the command prompt! Ok, not > it makes sense, and everything works. > > Thanks to all! You don't have to run python apps from the command line. Apps that throw up windows can usually be run by double-clicking the py file in windows. But apps that communicate solely on the terminal or console have to be run in that environment. -- https://mail.python.org/mailman/listinfo/python-list
Re: Need help in pulling SQL query out of log file...
On 14/10/2014 11:47 AM, Sagar Deshmukh wrote:
I have a log file which has lot of information like..SQL query.. number of
records read...records loaded etc..
My requirement is i would like to read the SQL query completly and write it to
another txt file..
Generally we encourage people to post what they've tried to the list. It
helps us identify what you know and what you need help with.
However, given:
> the log file may not be always same so can not make static choices...
You'll probably want to use regular expressions:
https://docs.python.org/howto/regex.html
Regexps let you search through the text for known patterns and extract
any that match. To extract all SQL query sections, you'll need to come
up with a way of uniquely identifying them from all other sections.
Looking at your example log file, it looks like they're all of the format:
SQL Query []
From that we can determine that all SQL queries are prefixed by 'SQL
Query [' and suffixed by ']', so the content you want is everything
between those markers. So a possible regular expression might be:
SQL Query \[(.*?)\]
To quickly explain this:
1. "SQL Query " matches on that string
2. Because [] have meaning for regexes, to match on literal
brackets you need to escape them via \[ and \]
3. ( ) is a group, whats contained in here will be returned
4. .* means to grab all matching text
5. ? means to do an "ungreedy" grab ie it'll stop at the first \]
it encounters.
Pulling the queries out of your log file should be as simple as:
import re
log = open('logfile').read()
queries = re.findall("SQL Query \[(.*?)\]", log, re.DOTALL)
Because the queries can fall across multiple lines, the re.DOTALL flag
is required to treat EOL markers as characters.
Hope this helps.
--
https://mail.python.org/mailman/listinfo/python-list
Re: TypeError: 'kwarg' is an invalid keyword argument for this function
On 13/10/2014 8:04 PM, Dave Angel wrote: It would also help to spell it the same. In the OP's implementation, he defined kwargs, and tried to use it as kwarg. That's perfectly okay, though: if `kwargs` is the name used to reference the dictionary of keyword arguments, `kwarg` would be an instance of a keyword argument. -- https://mail.python.org/mailman/listinfo/python-list
Re: Need help in pulling SQL query out of log file...
On Monday, 13 October 2014 22:40:07 UTC-7, alex23 wrote:
> On 14/10/2014 11:47 AM, Sagar Deshmukh wrote:
>
> > I have a log file which has lot of information like..SQL query.. number of
> > records read...records loaded etc..
>
> > My requirement is i would like to read the SQL query completly and write it
> > to another txt file..
>
>
>
> Generally we encourage people to post what they've tried to the list. It
>
> helps us identify what you know and what you need help with.
>
>
>
> However, given:
>
>
>
> > the log file may not be always same so can not make static choices...
>
>
>
> You'll probably want to use regular expressions:
>
>
>
> https://docs.python.org/howto/regex.html
>
>
>
> Regexps let you search through the text for known patterns and extract
>
> any that match. To extract all SQL query sections, you'll need to come
>
> up with a way of uniquely identifying them from all other sections.
>
> Looking at your example log file, it looks like they're all of the format:
>
>
>
> SQL Query []
>
>
>
> From that we can determine that all SQL queries are prefixed by 'SQL
>
> Query [' and suffixed by ']', so the content you want is everything
>
> between those markers. So a possible regular expression might be:
>
>
>
> SQL Query \[(.*?)\]
>
>
>
> To quickly explain this:
>
>
>
> 1. "SQL Query " matches on that string
>
> 2. Because [] have meaning for regexes, to match on literal
>
> brackets you need to escape them via \[ and \]
>
> 3. ( ) is a group, whats contained in here will be returned
>
> 4. .* means to grab all matching text
>
> 5. ? means to do an "ungreedy" grab ie it'll stop at the first \]
>
> it encounters.
>
>
>
> Pulling the queries out of your log file should be as simple as:
>
>
>
> import re
>
>
>
> log = open('logfile').read()
>
> queries = re.findall("SQL Query \[(.*?)\]", log, re.DOTALL)
>
>
>
> Because the queries can fall across multiple lines, the re.DOTALL flag
>
> is required to treat EOL markers as characters.
>
>
>
> Hope this helps.
Hi,
This helps and its working... Thank you so much
--
https://mail.python.org/mailman/listinfo/python-list
