Develop Reference

Python-How to execute code and store into variable?

So I have been struggling with this issue for what seems like forever now (I'm pretty new to Python). I am using Python 3.7 (need it to be 3.7 due to variations in the versions of packages I am using for the project) to develop an AI chatbot system that can converse with you based on your text input. The program reads the contents of a series of .yml files when it starts. In one of the .yml files I am developing a syntax for when the first 5 characters match a ^###^ pattern, it will instead execute the code and return the result of that execution rather than just output text back to the user. For example:
Normal Conversation:
- - What is AI?
- Artificial Intelligence is the branch of engineering and science devoted to constructing machines that think.
Service/Code-based conversation:
- - Say hello to me
- ^###^print("HELLO")
The idea is that when you ask it to say hello to you, the ^##^print("HELLO") string will be retrieved from the .yml file, the first 5 characters of the response will be removed, the response will be sent to a separate function in the python code where it will run the code and store the result into a variable which will be returned from the function into a variable that will give the nice, clean result of HELLO to the user. I realize that this may be a bit hard to follow, but I will straighten up my code and condense everything once I have this whole error resolved. As a side note: Oracle is just what I am calling the project. I'm not trying to weave Java into this whole mess.
THE PROBLEM is that it does not store the result of the code being run/executed/evaluated into the variable like it should.
My code:
def executecode(input):
print("The code to be executed is: ",input)
#note: the input may occasionally have single quotes and/or double quotes in the input string
result = eval("{}".format(input))
print ("The result of the code eval: ", result)
test = eval("2+2")
test
print(test)
return result
#app.route("/get")
def get_bot_response():
userText = request.args.get('msg')
print("Oracle INTERPRETED input: ", userText)
ChatbotResponse = str(english_bot.get_response(userText))
print("CHATBOT RESPONSE VARIABLE: ", ChatbotResponse)
#The interpreted string was a request due to the ^###^ pattern in front of the response in the custom .yml file
if ChatbotResponse[:5] == '^###^':
print("---SERVICE REQUEST---")
print(executecode(ChatbotResponse[5:]))
interpreter_response = executecode(ChatbotResponse[5:])
print("Oracle RESPONDED with: ", interpreter_response)
else:
print("Oracle RESPONDED with: ", ChatbotResponse)
return ChatbotResponse
When I run this code, this is the output:
Oracle INTERPRETED input: How much RAM do you have?
CHATBOT RESPONSE VARIABLE: ^###^print("HELLO")
---SERVICE REQUEST---
The code to be executed is: print("HELLO")
HELLO
The result of the code eval: None
4
None
The code to be executed is: print("HELLO")
HELLO
The result of the code eval: None
4
Oracle RESPONDED with: None
Output on the website interface
Essentially, need it to say HELLO for the "The result of the code eval:" output. This should get it to where the chatbot responds with HELLO in the web interface, which is the end goal here. It seems as if it IS executing the code due to the HELLO's after the "The code to be executed is:" output text. It's just not storing it into a variable like I need it to.
I have tried eval, exec, ast.literal_eval(), converting the input to string with str(), changing up the single and double quotes, putting \ before pairs of quotes, and a few other things. Whenever I get it to where the program interprets "print("HELLO")" when it executes the code, it complains about the syntax. Also, from several days of looking online I have figured out that exec and eval aren't generally favored due to a bunch of issues, however I genuinely do not care about that at the moment because I am trying to make something that works before I make something that is good and works. I have a feeling the problem is something small and stupid like it always is, but I have no idea what it could be. :(
I used these 2 resources as the foundation for the whole chatbot project:
Text Guide
Youtube Guide
Also, I am sorry for the rather lengthy and descriptive question. It's rare that I have to ask a question of my own on stackoverflow because if I have a question, it usually already has a good answer. It feels like I've tried everything at this point. If you have a better suggestion of how to do this whole system or you think I should try approaching this another way, I'm open to ideas.
Thank you for any/all help. It is very much appreciated! :)

The issue is that python's print() doesn't have a return value, meaning it will always return None. eval simply evaluates some expression, and returns back the return value from that expression. Since print() returns None, an eval of some print statement will also return None.
>>> from_print = print('Hello')
Hello
>>> from_eval = eval("print('Hello')")
Hello
>>> from_print is from_eval is None
True
What you need is a io stream manager! Here is a possible solution that captures any io output and returns that if the expression evaluates to None.
from contextlib import redirect_stout, redirect_stderr
from io import StringIO
# NOTE: I use the arg name `code` since `input` is a python builtin
def executecodehelper(code):
# Capture all potential output from the code
stdout_io = StringIO()
stderr_io = StringIO()
with redirect_stdout(stdout_io), redirect_stderr(stderr_io):
# If `code` is already a string, this should work just fine without the need for formatting.
result = eval(code)
return result, stdout_io.getvalue(), stderr_io.getvalue()
def executecode(code):
result, std_out, std_err = executecodehelper(code)
if result is None:
# This code didn't return anything. Maybe it printed something?
if std_out:
return std_out.rstrip() # Deal with trailing whitespace
elif std_err:
return std_err.rstrip()
else:
# Nothing was printed AND the return value is None!
return None
else:
return result
As a final note, this approach is heavily linked to eval since eval can only evaluate a single statement. If you want to extend your bot to multiple line statements, you will need to use exec, which changes the logic. Here's a great resource detailing the differences between eval and exec: What's the difference between eval, exec, and compile?

It is easy just convert try to create a new list and add the the updated values of that variable to it, for example:
if you've a variable name myVar store the values or even the questions no matter.
1- First declare a new list in your code as below:
myList = []
2- If you've need to answer or display the value through myVar then you can do like below:
myList.append(myVar)
and this if you have like a generator for the values instead if you need the opposite which means the values are already stored then you will just update the second step to be like the following:
myList[0]='The first answer of the first question'
myList[1]='The second answer of the second question'
ans here all the values will be stored in your list and you can also do this in other way, for example using loops is will be much better if you have multiple values or answers.

bibtex to html with pybtex, python 3

I want to take a file of one or more bibtex entries and output it as an html-formatted string. The specific style is not so important, but let's just say APA. Basically, I want the functionality of bibtex2html but with a Python API since I'm working in Django. A few people have asked similar questions here and here. I also found someone who provided a possible solution here.
The first issue I'm having is pretty basic, which is that I can't even get the above solutions to run. I keep getting errors similar to ModuleNotFoundError: No module named 'pybtex.database'; 'pybtex' is not a package. I definitely have pybtex installed and can make basic API calls in the shell no problem, but whenever I try to import pybtex.database.whatever or pybtex.plugin I keep getting ModuleNotFound errors. Is it maybe a python 2 vs python 3 thing? I'm using the latter.
The second issue is that I'm having trouble understanding the pybtex python API documentation. Specifically, from what I can tell it looks like the format_from_string and format_from_file calls are designed specifically for what I want to do, but I can't seem to get the syntax correct. Specifically, when I do
pybtex.format_from_file('foo.bib',style='html')
I get pybtex.plugin.PluginNotFound: plugin pybtex.style.formatting.html not found. I think I'm just not understanding how the call is supposed to work, and I can't find any examples of how to do it properly.

Here's a function I wrote for a similar use case--incorporating bibliographies into a website generated by Pelican.
from pybtex.plugin import find_plugin
from pybtex.database import parse_string
APA = find_plugin('pybtex.style.formatting', 'apa')()
HTML = find_plugin('pybtex.backends', 'html')()
def bib2html(bibliography, exclude_fields=None):
exclude_fields = exclude_fields or []
if exclude_fields:
bibliography = parse_string(bibliography.to_string('bibtex'), 'bibtex')
for entry in bibliography.entries.values():
for ef in exclude_fields:
if ef in entry.fields.__dict__['_dict']:
del entry.fields.__dict__['_dict'][ef]
formattedBib = APA.format_bibliography(bibliography)
return "<br>".join(entry.text.render(HTML) for entry in formattedBib)
Make sure you've installed the following:
pybtex==0.22.2
pybtex-apa-style==1.3

Why do I need to include statement inside `where` inside of quotes in this python-Spark case?

I am learning Spark and had the following code:
shakeWordsDF = (shakespeareDF
.select(explode(split(shakespeareDF.word,'[\s]+'))
.alias('word'))
.where('word'!='')
)
This code did not work because of "condition should be string or column".
However, the code by this guy worked
shakeWordsDF = (shakespeareDF
.select(explode(split(shakespeareDF.word,'[\s]+'))
.alias('word'))
.where("word!=''")
)
I understand what the eror says - it needs string. But why doesn't documentation have anything on strings? All tutorials I have seen say that it should be
.where(x>2)
or (if I'm not wrong)
.where('columnName'>2)
and not
.where("x>2").
I'm really confused.

How to "style" a text based hangman game

My question is simple, the hangman game looks like this:
I'm doing the indentation in a way I don't think is very good.
I just have var = "\t" and add it at the begging of every print, this seem impractical and hard to maintain.
Would you have it any other way? How is this generally managed?
Thanks in advance!

problem:
print('\tthis')
print('\tis')
print('\tan')
print('\texample')
solution = abstraction!:
def echo(string, indent=1): # name it whatever you want, e.g. p
print('\t'*indent + string)
echo('this')
echo('is')
echo('an')
echo('abstraction')
better solution = templates:
template = """
{partial}
______
{hangman}
|_________
Your points so far: {points}
You've entered (wrong): {wrong}
Choose a letter:
"""
print(
template.format(
partial=...,
hangman='\n'.join('|'+line for line in hangmanAscii(wrong=2).splitlines()),
points=...,
wrong=', '.join(...)
)
)

Templates aren't just for HTML.

A quick solution to your immediate problem is a helper function:
def put(text): print "\t" + text
For more interesting stuff, there is a library for terminal-based "graphical"-like applications. It is called "curses", and is available in python too: http://docs.python.org/library/curses.html. There is a tutorial here http://docs.python.org/howto/curses.html, and you can find more online.
Curses makes it possible to do more interesting text-based UI without too much effort. To just replicate what you have, you would probably create a window with the correct size and position (using newwin), and then print text to it without any indent (using addstr). Curses offers a lot of options and several modes of operation. It's not quick to learn, so only makes sense if you plan to do more with terminal based applications.

I'd probably fix the typo in "You word looks like this". Then look at printf style formatting, as described here.

Is it possible to encode (<em>asdf</em>) in python Textile?

I'm using python Textile to store markup in the database. I would like to yield the following HTML snippet:
(<em>asdf</em>)
The obvious doesn't get encoded:
(_asdf_) -> <p>(_asdf_)</p>
The following works, but yields an ugly space:
( _asdf_) -> <p>( <em>asdf</em>)
Am I missing something obvious or is this just not possible using python Textile?

It's hard to say if this is a bug or not; in the form on the Textile website, (_foo_) works as you want, but in the downloadable PHP implementation, it doesn't.
You should be able to do this:
([_asdf_]) -> <p>(<em>asdf</em>)</p>
However, this doesn't work, which is a bug in py-textile. You either need to use this:
(]_asdf_])
or patch textile.py by changing line 918 (in the Textile.span() method) to:
(?:^|(?<=[\s>%(pnct)s])|([{[]))
(the difference is in the final group; the brackets are incorrectly reversed.)
You could also change the line to:
(?:^|(?<=[\s>(%(pnct)s])|([{[]))
(note the added parenthesis) to get the behavior you desire for (_foo_), but I'm not sure if that would break anything else.
Follow up: the latest version of the PHP Textile class does indeed make a similar change to the one I suggested.