I am new to debugging. I simply want to see how the variables change as I run the program. I want to see what my program does and how.
But when I try to run the debugger, it shows the message: "Variables are not available":
Position the cursor on a line in your code where you are interested to see your variables.
Press Ctrl-F8 to toggle a breakpoint.
Debug your code.
Related
Above is a typical situation that I encounter. We hit an exception and now would like to get some more details about what went wrong. This is where I wish I could just jump right into an interactive python session and try to run the marked line manually to find out e.g. what the find_many might look like and if it actually does have a select method. How can I do this?
I think the Debug Console is what you are looking for. Press F1 and type debug console if you do not find the window.
You can use shift+enter or manual select the option like the following picture with the right mouse button.
I am not able to click(I can say it's diabled) step in, step out, step over option in pycharm debugger
I don't know if this is exactly what is causing your issues but here is one possibility:
All debugging options are grayed out in the menu if your cursor is on an empty line or a line that is a comment. Try putting your cursor on an actual line with code. The "Toggle Line Breakpoint" option in the "Run" menu should now become active. After starting the script with "Run -> Debug", the breakpoint will be triggered (assuming the code reaches it) and the other debug options such as "Step over" become available.
As mentioned in this answer: https://stackoverflow.com/a/48665161/2891209
Depending on what you're trying to debug it is possible for step-in to not show you code which isn't pure python. Pycharm will do the best it can of course, but if the function you're trying to debug isn't native python be prepared for anything...
If you're trying to step into a python wrapped C library function
Sometimes the debugger will skip over that code completely.
Sometimes you can walk the frames but the editor can't show you lines of code.
Sometimes you'll be able to step into an empty skeleton of a function.
It really depends on how the library was created.
I am a new Python user and I have been programming in Matlab, so I decided to use Spyder IDE (which looks pretty much like Matlab IDE).
Right now I want to debug through (execute line by line in order to understand) some python code that is written as a class with several built-in functions. So, I inserted a breakpoint at the __init__ function of the class, however, when I started a debugging it did not go to the specified breakpoint (since I have to call for a class initialization, rather than just code execution).
Is it possible to start class debugging from the command line?
In Matlab I would just call a function from the command line and it would stop at a specified breakpoint. Here I have to start a debugger, rahter than calling a function. If I simply call the following:
import energy_model
x = energy_model.EnergyModel()
It will just execute and ignore my breakpoint.
Hope my question is clear.
Thanks,
Mikhail
First up, make sure you are hitting the debug button in spyder, not the run button. The run button does not trigger breakpoints, so you will need to hit debug, and then continue to get to the first breakpoint in your code.
If that's failing, one option is to use the python debugger (pdb). This is entirely from the command-line, i.e. running debug commands and receiving debug information will also be through the command-line.
class EnergyModel:
__init__(self):
# set breakpoint
import pdb; pdb.set_trace()
...
Running from the command-line will then pause execution within the __init__ method.
Some of the commands you can issue pdb when the breakpoint is hit are listed here:
https://nblock.org/2011/11/15/pdb-cheatsheet/
Update #1
Example of a function that spyder can trigger breakpoints on
def test(a_string):
print(a_string) # breakpoint set here will be hit
test("hello world")
If you want to debug code in Spyder, it's probably best to run the module it's in by clicking the blue Play/Pause button for debug.
So how do we debug a module that is all classes or functions, with no script? We add script that only runs when this module was the one we clicked Play for, by putting it all under if __name__=="__main__":. (See here for more info on how that works.)
Then we can put a break point in the function or class we want to debug, call that from within if __name__==__"__main__":, run the module with the blue Play/Pause button, and access what's happening from the IPython console.
I am trying to debug code for QR Bar Code Labels in OpenERP 6 using Aptana Studio 3. I put a breakpoint in "pyqr" module, file "myfile.py", function "generate_image()", as per attached picture:
Now, when I run OpenERP server from Aptana IDE ("openerp-server.py" -> Debug As -> Python Run) and navigate to Manufacturing Orders where I can click on one of the right hand buttons "Large Label" or "Medium Label" or "Small Label", the debugger doesn't stop at the breakpoint and yet the label is printed in opened PDF file.
I have performed the following tests to check if the code in "myfile.py" executes. I have put "print" statement in "generate_image()" function, and it did not print anything in console. I put "import pdb" and "pdb.set_trace()" and the execution did not stop there. I added a message box in "generate_image()" function and message box did not display, yet the QR bar code label was created. It looks like that "myfile.py" code is not executed at all adding to mystery which code is executed that creates QR Bar Code labels.
How I can make debugger stop at this breakpoint? What am I missing?
To be able to debug in your IDE, I assume that you are running the Odoo server from source and start it from inside the IDE.
I'm not sure what is your actual setup, but maybe these pointers can help.
Try putting the breakpoint on a line of the method, instead of on it's definition.
Are you sure that the code is being executed? Try placing a print statement in it to confirm. Or try adding a import pdb; pdb.set_trace() line as a way to force a breakpoint.
Hi all Python developers!
In Eclipse with PyDev it is possible to edit a Python file while debugging. On save, the PyDev debugger will reload the updated code into the running program and uses my new code. How can I do the same thing in JetBrains PyCharm (using Community Edition)?
Eclipse / PyDev writes an output like this when I do that:
pydev debugger: Start reloading module: "MyWidget" ...
pydev debugger: Updated function code: <function close at 0x055F4E70>
pydev debugger: reload finished
I searched settings and web and could not find any hint. Very glad about any idea. Thx.
Edit: I found out in Eclipse/PyDev one has to be in debug mode to be able to use this feature. I tested in PyCharm, but there was no reload done.
PyCharm does not support edit and continue in either the community edition or the professional edition but here is a workaround that I have found while debugging.
Since you can run arbitrary code in the console and/or the expression evaluator, in a lot of cases, you can execute changes to the code without having to restart the application. This isn't exactly like edit-and-continue (which is a feature I really like in Visual Studio and should be part of Pycharm) but it goes a long way towards avoiding having to restart the program from scratch after a change to see if the new code works as expected.
Let me illustrate a couple of the techniques I use:
Let's say you have the following code (with a couple of typos/bugs to illustrate the techniques)
test_value = [10,9,8,7,6,55,4,3,2,1]
for i in range(0,10):
if test_value[i] == i:
print "found the value: " + i
If you run this code, first it errors because you can't print string plus integer but also I wanted to match on 5, not have 55 in the array. So here we go.
Set a break point on the for statement like this and run the code in the debugger.
When it breaks into the debugger, you realize that it should be 5 not 55. Rather than restarting, you can change line 1 to test_value = [10,9,8,7,6,5,4,3,2,1] then select the line, right click and choose Execute Line in Console... which will change the value of test_value to be the array with a 5. Now, the if statement on line 4 becomes true on the value 5. This will then trigger the syntax error on line 5.
Now if you want to make sure you have the syntax correct you can change line 5 to print "found the value: " + str(i), select the line and choose Evaluate Expression... from the right button context menu. When you click Evaluate, the result will show up either in the dialog (or in this case, since it is a print command, in the console)
Now that I've fixed these two issues, I can run the code successfully on the second pass rather than possibly multiple passes it might have taken if I didn't use these techniques. These techniques really pay off if you find a bug deep in the code where it took a while to set up.
Obviously, this is a very contrived example, but hopefully this shows how you can use both Evaluate Expression... and Execute Line in Console... to your advantage while debugging without having to restart your application each time you find a bug in the code.
Also, if you happen to be using Django, PyCharm (professional) will re-launch the server if you make changes to the code. So if you are looking at your web page and notice a problem, you can make a change to the code and switch back to the web page and as you do, either the running application or the debugged application will re-launch and the new code will be running when you refresh the page. Again, not really edit-and-continue but a pretty rapid way to make a change and test.
After all I found a useful and acceptable workaround for my question. It works in PyCharm Community Edition 3.1.2 and I assume it will do in commercial edition as well. I tested on a mid-scale project using Python 2.7.6, PySide (Qt) with one main window and 20+ widgets, tabs, whatever. Follow these steps...
Work in PyCharm on a python project :-)
Execute your code in Debug mode (did not tried Release so far)
Edit some code in one your modules imported during the life of your program
Make your program pause. To achieve this, you can click the "Pause" button of in PyCharms Debug view and then any place in your applications main window where it would need to do something (for example on a tab header). If you have a long a running task and no UI, you may place a breakpoint in a place your program often comes by.
In the Debug view, switch to the Console tab. There is a button on the left Show command line. Click this.
In the console, type in reload(MyModifiedModule) if this call fails, write import MyModifiedModule and try again.
Click resume in PyCharm.
Try the code you fixed.
There are some restrictions on this... It won't fix changes in your main method or main window, cause it won't be created again. In my tests I could not reload widgets from Qt. But it worked for classes like data containers or workers.
May the force be with you as you try this and do not hesitate to add your experiences.
I have the commercial version of PyCharm and just tried testing a simple python script. The script is the following:
for i in range(0,100):
print i
I ran the code in debug mode and placed a break point at the "print i" statement. When the debugger stopped during the first iteration I changed the code to look like this:
for i in range(0,100):
print i
print 'hello'
PyCharm did not reload/re-compile the altered script. Given this simple test my best guess would be that PyCharm does not dynamically reload .py files.
You can add hot reloading features by installing Reloadium plugin.
https://plugins.jetbrains.com/plugin/18509-reloadium
Example use (gif)
It also works without pycharm.
More details:
https://github.com/reloadware/reloadium