I am new to debugging in Python, and I currently use Hydrogen within Atom to do most of my Python work. I have looked into debugging, and it seems that the Python package pdb is the standard way to debug in Python. Most of the examples I can find seem to require using a command line on a .py file. However, in Hydrogen I would want to run it within the kernel on individual lines of the code, since I don't think pdb will work on a markdown (.md) file. Is there a way I can debug within my workflow, or do I need to make .py files of my code and run pdb on them?
I had read this answer and tried to implement "C. From Within Your Program". It had thrown errors, and I gave up. However, I went to the source that the answer had cited, and used this code:
import pdb
class MyObj(object):
def __init__(self, num_loops):
self.count = num_loops
def go(self):
for i in range(self.count):
pdb.set_trace()
print(i)
return
if __name__ == '__main__':
MyObj(5).go()
From this, I was able to get pdb to run in Hydrogen.
Related
Note:- Wait before you mark my question as duplicate please read it completely.
I wan't to run a python file using another.
I have tried using runpy,os.system & subprocess. The problem with subprocess and os.system command is that it fails for systems which have python2 and python3 both installed if i just run with python. If i run it with python3 i fails for people having single installation.
The problem with runpy is that it does not work according to my needs.
The following is run my directory structure
test\
average\
average.py
average_test.py
many similar directories like average...
run_tests.py
The content of average is
def average(...args):
# Do something
The content of average_test.py
from average import average
def average_test():
assert average(1,2,3) == 2
Now if i use runpy.run_path it throws a ImportError saying average is not a module. The os.system and subprocess.call works perfectly but I hope my "testing_framework" will be used by many so I can't use the above two functions. Isn't there any other way to do it. I have researched the whole of SO and google but didn't find a solutions.
Also sys.path.append/insert will not help as I can't tell my "users" to add this to every file of theirs.
Is there no easy way to do it? I mean like pytest accomplishes this so there must be a way.
Thank you moderators for reading my question.
EDIT I forgot to mention that I wan't the code to be run in if __name__ == '__main__' block too and I have also tried using a snippet from another SO answer which fails too. The snippet was
def exec_full(filepath):
global_namespace = {
"__file__": filepath,
"__name__": "__main__",
}
with open(filepath, 'rb') as file:
exec(compile(file.read(), filepath, 'exec'), global_namespace)
Please note that the directory structure was just an example the user may have a different code/directory structure.
NOTE:- I found the answer. I needed to do subprocess.call([sys.executable,file_path]). sys.executable returns the path for the python executable file for the current version.
Create an empty __init__.py in average folder
And then try to import
from average import average
it would work like charm :)
test\
average\
average.py
average_test.py
__init__.py
many similar directories like average...
run_tests.py
I have a python script (we'll say "script.py") that I want to grab values from using a separate GUI python script ("GUI.py"). When I run my GUI.py script, I want to have these text fields in the GUI sent over to script.py after clicking a button in the GUI. I am thinking that my best solution might be to have the GUI.py create another script ("lib.py") that holds all these values and it just writes to it. It then runs the "script.py" script. So all in all the GUI.py will have a function that when called will look something like this:
def on_button(self):
username = self.usernameInput.get()
file = open(“lib.py”,”w”)
file.write(“username = ” + username)
os.system("script.py")
I think this will work, but I am just wondering, does this seem like a practical solution? Let me know what you guys think.
No, I don't think this is the practical solution.
Do you consider instead making the python script you want to run into a module or package that you can call directly inside your GUI? I think that is the cleanest approach. For using your scripts as modules, see the docs or for 2.7.
Basically a module is a python file, script.py, and as long as it is in the python path (say, your current directory), you can import it:
from script import action
So you could try:
def on_button(self):
username = self.usernameInput.get()
result = action(username) # and any other args you want to pass
print(result)
That is, if the script in question uses a if __name__ == "__main__": statement (or can otherwise be run from the command line), try putting the operations in some def action(args): function and importing it into your GUI.
In python ,There is a reload method to reload an imported module , but is there a method to reload the currently running script without restarting it, this would be very helpful in debugging a script and changing the code live while the script is running. In visual basic I remember a similar functionality was called "apply code changes", but I need a similar functionality as a function call like "refresh()" which will apply the code changes instantly.
This would work smoothly when an independent function in the script is modified and we need to immediately apply the code change without restarting the script.
Inshort will:
reload(self)
work?
reload(self) will not work, because reload() works on modules, not live instances of classes. What you want is some logic external to your main application, which checks whether it has to be reloaded. You have to think about what is needed to re-create your application state upon reload.
Some hints in this direction:
Guido van Rossum wrote once this: xreload.py; it does a bit more than reload() You would need a loop, which checks for changes every x seconds and applies this.
Also have a look at livecoding which basically does this. EDIT: I mistook this project for something else (which I didn't find now), sorry.
perhaps this SO question will help you
Perhaps you mean something like this:
import pdb
import importlib
from os.path import basename
def function():
print("hello world")
if __name__ == "__main__":
# import this module, but not as __main__ so everything other than this
# if statement is executed
mainmodname = basename(__file__)[:-3]
module = importlib.import_module(mainmodname)
while True:
# reload the module to check for changes
importlib.reload(module)
# update the globals of __main__ with the any new or changed
# functions or classes in the reloaded module
globals().update(vars(module))
function()
pdb.set_trace()
Run the code, then change the contents of function and enter c at the prompt to run the next iteration of the loop.
test.py
class Test(object):
def getTest(self):
return 'test1'
testReload.py
from test import Test
t = Test()
print t.getTest()
# change return value (test.py)
import importlib
module = importlib.import_module(Test.__module__)
reload(module)
from test import Test
t = Test()
print t.getTest()
Intro
reload is for imported modules. Documentation for reload advises against reloading __main__.
Reloading sys, __main__, builtins and other key modules is not recommended.
To achieve similar behavior on your script you will need to re-execute the script. This will - for normal scripts - also reset the the global state. I propose a solution.
NOTE
The solution I propose is very powerful and should only be used for code you trust. Automatically executing code from unknown sources can lead to a world of pain. Python is not a good environment for soapboxing unsafe code.
Solution
To programmatically execute a python script from another script you only need the built-in functions open, compile and exec.
Here is an example function that will re-execute the script it is in:
def refresh():
with open(__file__) as fo:
source_code = fo.read()
byte_code = compile(source_code, __file__, "exec")
exec(byte_code)
The above will in normal circumstances also re-set any global variables you might have. If you wish to keep these variables you should check weather or not those variables have already been set. This can be done with a try-except block covering NameError exceptions. But that can be tedious so I propose using a flag variable.
Here is an example using the flag variable:
in_main = __name__ == "__main__"
first_run = "flag" not in globals()
if in_main and first_run:
flag = True
None of these answers did the job properly for me, so I put together something very messy and very non-pythonic to do the job myself. Even after running it for several weeks, I am finding small issues and fixing them. One issue will be if your PWD/CWD changes.
Warning this is very ugly code. Perhaps someone will make it pretty, but it does work.
Not only does it create a refresh() function that properly reloads your script in a manner such that any Exceptions will properly display, but it creates refresh_<scriptname> functions for previously loaded scripts just-in-case you need to reload those.
Next I would probably add a require portion, so that scripts can reload other scripts -- but I'm not trying to make node.js here.
First, the "one-liner" that you need to insert in any script you want to refresh.
with open(os.path.dirname(__file__) + os.sep + 'refresh.py', 'r') as f: \
exec(compile(f.read().replace('__BASE__', \
os.path.basename(__file__).replace('.py', '')).replace('__FILE__', \
__file__), __file__, 'exec'))
And second, the actual refresh function which should be saved to refresh.py in the same directory. (See, room for improvement already).
def refresh(filepath = __file__, _globals = None, _locals = None):
print("Reading {}...".format(filepath))
if _globals is None:
_globals = globals()
_globals.update({
"__file__": filepath,
"__name__": "__main__",
})
with open(filepath, 'rb') as file:
exec(compile(file.read(), filepath, 'exec'), _globals, _locals)
def refresh___BASE__():
refresh("__FILE__")
Tested with Python 2.7 and 3.
Take a look at reload. You just need to install the plugin an use reload ./myscript.py, voilà
If you are running in an interactive session you could use ipython autoreload
autoreload reloads modules automatically before entering the execution of code typed at the IPython prompt.
Of course this also works on module level, so you would do something like:
>>>import myscript
>>>myscript.main()
*do some changes in myscript.py*
>>>myscript.main() #is now changed
In Sublime Text 3 I have a few packages that open new files within the window. They have functions that look like:
class BufferCommand(sublime_plugin.WindowCommand):
def run(self):
view = self.window.new_file()
...
I grabbed this for something I am working on, and couldn't get a new file to generate, even though that works for the plugin I snagged it from, and is similar to how it is used in Packages/Default/new_templates.py. After some more searching, I found the following code, and it works as expected
class TestCommand(sublime_plugin.TextCommand):
def run(self,edit):
view = self.view.window().new_file()
Can somebody tell me why?
It might be the way you are running your command? If you are entering
view.run_command("buffer")
into the python console, then nothing will happen if BufferCommand is not a TextCommand.
Instead try this:
window.run_command("buffer")
This should fix your problem.
I'm trying to save myself just a few keystrokes for a command I type fairly regularly in Python.
In my python startup script, I define a function called load which is similar to import, but adds some functionality. It takes a single string:
def load(s):
# Do some stuff
return something
In order to call this function I have to type
>>> load('something')
I would rather be able to simply type:
>>> load something
I am running Python with readline support, so I know there exists some programmability there, but I don't know if this sort of thing is possible using it.
I attempted to get around this by using the InteractivConsole and creating an instance of it in my startup file, like so:
import code, re, traceback
class LoadingInteractiveConsole(code.InteractiveConsole):
def raw_input(self, prompt = ""):
s = raw_input(prompt)
match = re.match('^load\s+(.+)', s)
if match:
module = match.group(1)
try:
load(module)
print "Loaded " + module
except ImportError:
traceback.print_exc()
return ''
else:
return s
console = LoadingInteractiveConsole()
console.interact("")
This works with the caveat that I have to hit Ctrl-D twice to exit the python interpreter: once to get out of my custom console, once to get out of the real one.
Is there a way to do this without writing a custom C program and embedding the interpreter into it?
Edit
Out of channel, I had the suggestion of appending this to the end of my startup file:
import sys
sys.exit()
It works well enough, but I'm still interested in alternative solutions.
You could try ipython - which gives a python shell which does allow many things including automatic parentheses which gives you the function call as you requested.
I think you want the cmd module.
See a tutorial here:
http://wiki.python.org/moin/CmdModule
Hate to answer my own question, but there hasn't been an answer that works for all the versions of Python I use. Aside from the solution I posted in my question edit (which is what I'm now using), here's another:
Edit .bashrc to contain the following lines:
alias python3='python3 ~/py/shellreplace.py'
alias python='python ~/py/shellreplace.py'
alias python27='python27 ~/py/shellreplace.py'
Then simply move all of the LoadingInteractiveConsole code into the file ~/py/shellreplace.py Once the script finishes executing, python will cease executing, and the improved interactive session will be seamless.