My question: I need to save the output from a SPARC solver (which is currently appearing as text in the terminal) as a variable in my Python code. How can I do this?
Quick note: SPARC is a solver used for ASP (answer-set-programming) files - just mentioning this so that people don't get confused and think I am referring to asp.net.
I am running a Python file and an ASP file (in query mode) simultaneously, in the same terminal, using the command python pythonfile.py | java -jar sparc.jar aspfile.sp. Output from the python file in the form of sys.stdout.write() is being redirected as the input to the SPARC solver; i.e. the text I output becomes the query that is solved using my ASP code. This is working, and generating the output I want, but I can't figure out how to use that output in my Python code.
This is a follow-up to another question I have asked, found here. In that question I was trying to find out how to run an ASP file from my C++ code. I went with option 2 in the answer I was given, and am using redirected stdout with the two files running as separate processes. Please note one major change since the original question: I am now using Python instead of C++.
Further details if required: My Python version is 2.7 and my operating system is Ubuntu 14.04. I don't think it's relevant but, in case it is, you should know that my Python code is also being used to control a Gazebo Turtlebot simulation, and I am using ROS Indigo to run that simulation. I won't post my code unless someone requests it, as I just want an idea of what method I could use (I can't find anything that works on the internet), rather than needing my code debugged / assistance writing it. However I will post below an example of what is output to the terminal when my code runs, as this is the information I am trying to 'capture'.
SPARC V2.52
program translated
?- yes
?- no
It is the answers 'yes' and 'no' that I want to save as variables in my Python file.
SOLUTION:
For anyone wanting to do the same thing, I followed the answer provided by CaptainTrunky.
First I run the command python pythonfile.py | java -jar sparc.jar aspfile.sp > sparc.out, saving the SPARC output to the text file sparc.out.
Then I run python outputParser.py to run a script that prints the contents of the text file, allowing me to check that I'm manipulating the data correctly. The script is very simple:
lines = [line.strip('?- ') for line in open('sparc.out')]
lines = [line.strip('\n') for line in lines]
print lines
You can use python to read from sys.stdin with a script similar to the following (filter.py):
import sys
for line in sys.stdin.readlines():
if line.startswith('?- '):
print line.strip()
Then invoke your pipeline like this:
python pythonfile.py | java -jar sparc.jar aspfile.sp | python filter.py
I would suggest you do dump SPARK output to text file and then to parse it with you tool.
Write a shell script that does it for you:
python pythonfile.py | java -jar sparc.jar aspfile.sp > spark.out
python parse_out.py spark.out
Related
I edited my question, hope it is described better now.
I am working on a software that gives me a nice PDF with lots of matplotlib graphics, depending on the data I get.
So think of a database of pages and then the software decides which pages are chosen and filled with changed images, The text stays the same.
So for instance for data1 I get page1-4 and page7 and page 9. For data2 I get page1-4 and page6. Saved as PDF. I am doing this manually with Quark which needs to be changed. I hope I can figure out the scripting to do so.
But for starters I cant start scribus from the developing enviroment. Eclipse Anaconda on Ubuntu.
import subprocess
subprocess.run('scribus')
works fine in terminal, but gives me an error in Eclipse which I cant figure out.
File "/home/b256/anaconda3/envs/test/lib/python3.7/site.py", line 178
file=sys.stderr)
^
SyntaxError: invalid syntax
This seems to be some Python 2 error in the site.py file
???? Is this some anaconda python path error ??
It's not really clear to me, what you want to achieve, but you're welcome to have a look at a script of mine:
https://github.com/aoloe/scribus-script-repository/blob/master/imposition/imposition.py
This is probably a bit more complex than what you are trying to achieve:
the script gets started from the terminal,
if it notices that it has not been started from inside of Scribus (the exception on import scribus)...
... it starts Scribus with itself as the Script to be run.
the script runs again, this time from inside of Scribus...
... now there is no exception when importing scribus and the body of the script runs.
Of course, it's simpler if you start a script that launches Scribus with other scripts.
For you the most important line is probably:
call(['scribus', '-g', '-py', sys.argv[0]] + arguments + ['--', file])
It's starting Scribus from Python
with as little GUI as possible (-g) and
launches the script sys.argv[0]
with a few arguments and
after the -- tells Scribus what file to open.
Is there a way to run python 2 code within a python 3 file?
I have to use a function that is coded in python 2 and is located in a python 2 file. But i need to import it and use the function within a python 3 file. Is is possible to run that function is like a python 2 mode?
It is not possible to run Python 2 code with Python 3, at least not in general. Although converting by hand is fairly straight-forward.
If you have long files you should also consider using 2to3 which will apply the needed fixes to make your code run with Python 3.
If you already have Python 3 installed you simply have to run the following in your terminal.
2to3 your_file_name.py
Note that sometimes 2to3 will be unable to transpile from Python2 to Python3. If it notices it, it will give you warnings and indicate what lines you have to fix manually.
Although, it can also happen that 2to3 doesn't even notice the output code will not work. This is what happened in the example you gave me in the comments:
input('Type text here: ').encode('utf-8').encode('hex')
This will not work in Python3 for reasons that you can explore here.
The reason 2to3 doesn't realize it is because this is actually syntactically perfectly valid code. And actually you could foreshadow input or str.encode in a way that would make this working code.
In conclusion, sometime you have to read the error and fix the code yourself.
I have some programming assignments which read input data from stdin like this:
text = sys.stdin.readline().strip()
I am using Spyder as my development environment, and am not able to find a way to give the stdin. So, I added a -infile option to the code, and am reading from the file.
However, when submitting, I need to revert back to reading the stdin. How can I read stdin in the first place? I know how to do this from linux command line, but for now have to use windows.
(Spyder maintainer here) The code you posted only works to read text when you run it in a system terminal (i.e. bash or cmd.exe).
It doesn't work in Spyder because its terminals are implemented in a different technology (PyQt vs. readline).
I am trying to use the input feature on python for my program. I installed SublimeREPL but I still cant seem to figure out how to provide an input for my program. (coming from a complete beginner)
Using input from within an editor can be tricky. A simple solution would be to run your program from the command line. Open a terminal and change into the directory where your script user_inputs_intro.py is located and type:
python user_inputs_intro.py
Now, you will see the Tell me something: and should be able to type something that will be echoed back after you press enter.
I have just downloaded Python 3.3.2 to use on windows7 and run the msi file to install. After installation I have tried using the prog only to find that every time I run my initial print 'hello world' it keeps reporting a syntax error.
I have tried both single and double quotes but each time reports a syntax. It will add say 8 + 9 and return the answer but no joy with using a print statement.
I have tried both the shell and a new window but without success.
Any advice please much appreciated.
If you are using Python 3.x, you have to do print('hello world').
In Python 2.x, print was a statement, like if, for, etc. Now it is a function, thus the ().
You're probably using instructions for a python-2 program, where print was a statement, rather than a function. In python >= 3, you have to do print(something), rather than just print something.