I am debugging a Python program in Eclipse.
I have a breakpoint in a big loop and I expect the problem to occur in the (1000+)th round. How can I reach that ASAP instead of clicking resume 1000 times?
You want to set a conditional breakpoint. Read through the link I provided for an explanation and example in python.
Ctrl-R is the equivalent to placing a breakpoint on the cursor's line and clicking the "Resume" button, except that it doesn't litter your system with unnecessary breakpoints.
Is this what you are looking for?
Take a look at this: http://www.clear.rice.edu/comp310/Eclipse/debugging.html
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'd like to know if drop frame is available in PyCharm / Intellij with Python plugin.
Here's what the button looks like (it doesn't show up on the debug toolbar so I assume it's just not available for PyCharm) -->
How to step one step back in IntelliJ?
What I'm trying to do is to re-play a function when I see a problem, to inspect it more. ("come back in time")
(I've used this before in Eclipse with Java, it would replay the current scope if you edited it and saved changes. of course the global scope remains changed after running a function many times, but for most cases it's very useful)
Thanks for telling!
As of version 2017.3.3, there is no drop frame feature as that in IntelliJ. The pycharm docs referred above seems wrong.
Since you want to 're-ply a function', 'Evaluate Expression' works great for that purpose. I use a lot when I debug. It basically allows to run any code at runtime with the variables and functions in that context.
It is the icon on the most right on the debug window.
Put a break point on the line before the line where goes wrong, debug the program, when it tops on the break point, click on 'Evaluate Expression' icon, copy the function with issues, paste it and run it.
PyCharm 2017.2 seems to have added the functionality you're looking for. The documentation describes a "Drop frame button" on the Debug Stepping Toolbar:
Interrupts execution and returns to the initial point of method execution. In the process, it drops the current method frames from the stack.
Ok, in fact, I did found a way how to single step into the code, but I still can't use the f4,f7 buttons to do it on my keyboard. Can anyone help ?
I have an easy question which concerns the flow of execution : http://www.openbookproject.net/thinkcs/python/english3e/functions.html
I'm referring to the following paragraph :
In PyScripter, we can watch the flow of execution by “single-stepping” through any program. PyScripter will highlight each line of code just before it is about to be executed.
PyScripter also lets us hover the mouse over any variable in the program, and it will pop up the current value of that variable. So this makes it easy to inspect the “state snapshot” of the program — the current values that are assigned to the program’s variables.
This is a powerful mechanism for building a deep and thorough understanding of what is happening at each step of the way. Learn to use the single-stepping feature well, and be mentally proactive: as you work through the code, challenge yourself before each step: “What changes will this line make to any variables in the program?” and “Where will flow of execution go next?”
Let us go back and see how this works with the program above that draws 15 multicolor squares. First, we’re going to add one line of magic below the import statement — not strictly necessary, but it will make our lives much simpler, because it prevents stepping into the module containing the turtle code.
import turtle
__import__("turtle").__traceable__ = False
Now we’re ready to begin. Put the mouse cursor on the line of the program where we create the turtle screen, and press the F4 key. This will run the Python program up to, but not including, the line where we have the cursor. Our program will “break” now, and provide a highlight on the next line to be executed, something like this:
I don't know why, but when I press on F4 I only get my computer's options concerning the screen. Do you have any idea how I could correct this?
Thank you!
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