Re: [Tutor] nosetests on travis-ci.org
>python-l...@python.org >also available on Usenet as comp.lang.python, as it tends to have people >with a much broader range of experience than here. But even there, >you'll probably be asked to come up with a minimum example that >demonstrates the problem: Also try on IRC chat.freenode.net There might be a channel of travis-ci and people might help you. _ Joaquin This email is confidential and may be subject to privilege. If you are not the intended recipient, please do not copy or disclose its content but contact the sender immediately upon receipt. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] Python code
Hello, I am new to python and need help with this question: Compose a function odd ( ) that takes three bool arguments and returns True if an odd number of arguments are True and False otherwise. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Python code
On Tue, Nov 01, 2016 at 05:28:34PM -0400, Haley Sandherr wrote: > Hello, I am new to python and need help with this question: > > Compose a function odd ( ) that takes three bool arguments and returns > True if an odd number of arguments are True and False otherwise. What part are you having trouble with? Can you show us what code you have tried to write? Do you know how to define a function that takes three arguments? Here's an example of a function that takes FOUR arguments and does nothing: def my_function(m, b, x, p): pass Can you...? - change the name of the function? - change it so that it takes three arguments rather than four? - choose more sensible names for the arguments? - change the "do nothing" body (pass) to make it do something more useful? Start by doing that, and if you still need help, show us the code you have come up with and we'll continue from there. -- Steve ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] implementing sed - termination error
Hi Running a test on a linux box, with python. Trying to do a search/replace over a file, for a given string, and replacing the string with a chunk of text that has multiple lines. >From the cmdline, using sed, no prob. however, implementing sed, runs into issues, that result in a "termination error" The error gets thrown, due to the "\" of the newline. SO, and other sites have plenty to say about this, but haven't run across any soln. The test file contains 6K lines, but, the process requires doing lots of search/replace operations, so I'm interested in testing this method to see how "fast" the overall process is. The following psuedo code is what I've used to test. The key point being changing the "\n" portion to try to resolved the termination error. import subprocess ll_="ffdfdfdfg" ll2_="12112121212121212" hash="a" data_=ll_+"\n"+ll2_+"\n"+qq22_ print data_ cc='sed -i "s/'+hash+'/'+data_+'/g" '+dname print cc proc=subprocess.Popen(cc, shell=True,stdout=subprocess.PIPE) res=proc.communicate()[0].strip() === error sed: -e expression #1, char 38: unterminated `s' command ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] implementing sed - termination error
On 02/11/16 00:18, bruce wrote: > Trying to do a search/replace over a file, for a given string, and > replacing the string with a chunk of text that has multiple lines. > > From the cmdline, using sed, no prob. however, implementing sed, runs > into issues, that result in a "termination error" I don;t understand what you mean by that last paragraph. "using sed, no prob" implies you know the command you want to run because you got it to work on the command line? If that's correct can you share the exact command you typed at the command line that worked? "implementing sed" implies you are trying to write the sed tool in Python. but your code suggests you are trying to run sed from within a Python script - very different. > The error gets thrown, due to the "\" of the newline. That sounds very odd. What leads you to that conclusion? For that matter which \ or newline? In which string - the search string, the replacement string or the file content? > The test file contains 6K lines, but, the process requires doing lots > of search/replace operations, so I'm interested in testing this method > to see how "fast" the overall process is. I'm not sure what you are testing? Is it the sed tool itself? Or is it the Python script that runs sed? Or something else? > The following psuedo code is what I've used to test. Pseudo code is fine to explain complex algorithms but in this case the actual code is probably more useful. > The key point > being changing the "\n" portion to try to resolved the termination > error. Again, I don't really understand what you mean by that. > import subprocess > > ll_="ffdfdfdfg" > ll2_="12112121212121212" > hash="a" > > data_=ll_+"\n"+ll2_+"\n"+qq22_ > print data_ > > cc='sed -i "s/'+hash+'/'+data_+'/g" '+dname > print cc I assume dname is your file? I'd also use string formatting to construct the command, simply because sed uses regex and a lot of + signs looks like a regex so it is confusing (to me at least). But see the comment below about Popen args. > > proc=subprocess.Popen(cc, shell=True,stdout=subprocess.PIPE) > res=proc.communicate()[0].strip() > > > > === > error > sed: -e expression #1, char 38: unterminated `s' command My first instinct when dealing with subprocess errors is to set shell=False to ensure the shell isn't messing about with my inputs. What happens if you set shell false? I'd also tend to put the sed arguments into a list rather than pass a single string. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Python code
On 01/11/16 21:28, Haley Sandherr wrote: > Hello, I am new to python and need help with this question: What kind of help? What exactly do you find difficult? > > Compose a function odd ( ) Can you define a function? Any function? > that takes three bool arguments Can you define a function that takes arguments - any arguments? Can you define one that takes exactly 3 arguments? > and returns True Can you define a function that returns a value - any value? Can you define a function that returns True? > if an odd number of arguments are True and False otherwise. Can you test if a value is True? Can you test if 2 out of 3 are True? (There are several ways to do this! Some easy and some harder but shorter ) How far down that list do you get before becoming stuck? I could show you a single line solution, but I doubt you would learn very much from it. It is better for you to come up with your own solution where you actually understand what every line of code does. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Python code
On Nov 1, 2016 4:57 PM, "Haley Sandherr" wrote: > > Hello, I am new to python and need help with this question: > > Compose a function odd ( ) that takes three bool arguments and returns True if an odd number of arguments are True and False otherwise. Do you understand all of the terms in the question? Are there terms in the question that you don't know? Try a simpler, related problem if you are getting stuck: it may help point the way forward. For example, your original question has three arguments. Can you do the problem variation that just has one boolean argument? Call this odd1(). You can see that it's like the original problem. If you can do this, try writing odd2(): a function that can deal with two arguments. Can you do this? What other similar functions have you seen so far? These questions are intended to help us calibrate our mental model of what you currently understand. Please tell us more do we can give you appropriate answers. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] implementing sed - termination error
On 01Nov2016 20:18, bruce wrote: Running a test on a linux box, with python. Trying to do a search/replace over a file, for a given string, and replacing the string with a chunk of text that has multiple lines. From the cmdline, using sed, no prob. however, implementing sed, runs into issues, that result in a "termination error" Just terminology: you're not "implementing sed", which is a nontrivial task that would involve writing a python program that could do everything sed does. You're writing a small python program to call sed to do the work. Further discussion below. The error gets thrown, due to the "\" of the newline. SO, and other sites have plenty to say about this, but haven't run across any soln. The test file contains 6K lines, but, the process requires doing lots of search/replace operations, so I'm interested in testing this method to see how "fast" the overall process is. The following psuedo code is what I've used to test. The key point being changing the "\n" portion to try to resolved the termination error. import subprocess ll_="ffdfdfdfg" ll2_="12112121212121212" hash="a" data_=ll_+"\n"+ll2_+"\n"+qq22_ print data_ Presuming qq22_ is not shown. cc='sed -i "s/'+hash+'/'+data_+'/g" '+dname print cc proc=subprocess.Popen(cc, shell=True,stdout=subprocess.PIPE) res=proc.communicate()[0].strip() There are two fairly large problems with this program. The first is your need to embed newlines in the replacement pattern. You have genuine newlines in your string, but a sed command would look like this: sed 's/a/ffdfdfdfg\ 12112121212121212\ q/g' so you need to replace the newlines with "backslash and newline". Fortunately strings have a .replace() method which you can use for this purpose. Look it up: https://docs.python.org/3/library/stdtypes.html#str.replace You can use it to make data_ how you want it to be for the command. The second problem is that you're then trying to invoke sed by constructing a shell command string and handing that to Popen. This means that you need to embed shell syntax in that string to quote things like the sed command. All very messy. It is better to _bypass_ the shell and invoke sed directory by leaving out the "shell=True" parameter. All the command line (which is the shell) is doing is honouring the shell quoting and constructing a sed invocation as distinct strings: sed -i s/this/that/g filename You want to do the equivalent in python, something like this: sed_argv = [ 'sed', '-i', 's/'+hash+'/'+data_+'/g', dname ] proc=subprocess.Popen(sed_argv, stdout=subprocess.PIPE) See how you're now unconcerned by any difficulties around shell quoting? You're now dealing directly in strings. There are a few other questions, such as: if you're using sed's -i option, why is stdout a pipe? And what if hash or data_ contain slashes, which you are using in sed to delimit them? Hoping this will help you move forward. Cheers, Cameron Simpson ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
