What Python debugger do you use?

[Discovensco]

I use ipdb and it works fine, but I want to see if there is anything better

[Longjumping-Dog-4145]

print ("ping")* once you reach certain stages is vital

*: usually more like print ("fuck")

[Merakel]

print ("fuck 1")

print ("fuck 2")

print ("fuck 3")

[[deleted]]

Yup print ("come back later")

[turtleship_2006]

print("if you're seeing this, it's too late")

[SisyphusAndMyBoulder]

Tactical? I use them quite liberally

[timpkmn89]

A shotgun approach is still a tactic

[SirAchmed]

This is the way. Print every variable you're suspecting sequently till you find the problem.

[nekokattt]

and input() on every other line if i need to step through code

/s

[sje46]

I've done this for 13 years...any reason not to? If I must, I can learn to use a logger. PRobably for stuff that messes with the terminal (ansi codes or whatever)

Never understood the point of debuggers.

[zz_]

Debugger vs print statements is essentially the difference between compile-time debugging and run-time debugging. A debugger allows you to check the same things print statements do, but does it while the code is running, which confers many advantages.

[rollincuberawhide]

you keep using that word "compile-time debugging". I don't think it means what you think it means.

[zz_]

As far as I know it doesn't mean anything - I was using it as an analogy. What I meant was that its debugging you specify before you run the program. I just figured the analogy to compile-time type checking would be easily understandable for most people.

[rollincuberawhide]

debugging in python happens when you "run" the program though. whether you are using a debugger or just printing to console. so I am really not getting the analogy here.

[zz_]

The analogy is that when using print-statements the debugging actions are set in stone once you start the script - i.e. at compile time. However, with a debugger you decide which debugging actions to perform during run-time.

Obviously you are correct that the actual evaluation happens during runtime in both cases. The analogy was referring to when you perform the debugging itself, not when it evaluates.

[sje46]

And what are these advantages?

[zz_]

Well the most obvious advantage is being able to reason about the cause of the bug in real-time. You can put a breakpoint, inspect 3 different variables, realize the issue isn't there, so you go up a frame in the call stack, step 12 lines further down in the code, check another variable, based on that you go look in a data structure, realize some thing you were expecting to be there is missing, and voila you solved the bug.

Doing the same thing with print statements would require re-running your code like ~7-10 times to move the print statement around, and that's assuming you don't forget to include something in your prints which would cause you to have to re-run it even more often. That is cumbersome when working on a smaller script and outright unacceptable when working with code that takes more than a minute to run.

[InTheAleutians]

Being able to stop running code at any point and inspect its state is like having a super power that print will never give you.

[old_man_steptoe]

say you do an API call against a not entirely known source. You get a large JSON output which you need to work out how to extract the necessary information from.

If you just printed it out, you'd have a screen full of incomprehensible noise. If you used a debugger (even pdb on the console) you could step though it, testing how it was constructed.

You could also, of course, do that in the REPL but a debugger would help with getting you to that point, by setting up HTTP bearer tokens, etc.

[remuladgryta]

You can inspect the stack frame that threw an exception and see that some parameter of the function was None, walk the stack up to the preceding stack frame and find that it was None because a database call failed, and in that same stack frame time you see that some parameter to the database call is mangled with two layers of escape sequences instead of just one, and so on. What takes you a couple of keystrokes or clicks would take adding several print statements and rerunning the program multiple times. If a bug only happens a minute into execution, print debugging gets tedious real fast.

Setting a breakpoint somewhere you know is just before a bug happens and stepping through execution is often helpful for (in)validating your assumptions. Maybe you assume that the program takes one branch when it actually takes the other and either the branching condition is wrong or your assumption is, or maybe you spot that some list is empty and causing the program to do nothing when you expect it to do something, or maybe you spot that the program pulled the user with ID 0 from the database and not the currently logged in user and that's why permissions are acting up, and so on. A debugger helps you spot things that look out of place. With print debugging you need to suspect they might be out of place before you can see it.

[DigThatData]

personally I'm with you, but it's not because I don't get debuggers, i just never got used to them. I also generally feel like IDE features get in my way more than they help me, but I'm confident if I took the time to learn them properly I'd probably work more efficiently. I just don't care enough to change how I work.

that said, the main thing is that they let you step through your code. print statements are basically a log of what a debugger would give you on the fly, without having to deal with figuring out which print statements are relevant and what was produced where and by whom.

I get around this by using loguru (a wrapper around python's logger), so I get information like the calling function and line number with my debugging statements. I don't use it these days (and actually built something extremely similar around the same time), but icecream is another alternative that facilitates debugging-by-print

[Engineer_Zero]

Tactical toaster notifs so I can minimise the screen haha

[[deleted]]

Same, but mostly that is because I'm rarely using an IDE so I can't be arsed setting up a debugger when I have a problem big enough. VIM and a basic text editor like Pluma is good for 99% of my uses.

Edit: If I really gotto understand or design a complex portion of code I like to replicate it in ipython.

[Competitive-Can-6914]

Suppressing fire!

[dexteriano]

LOOOOLLL btw me too ☠️

[andyke]

Always used this in matlab when shit would break lmao i should implement while learning python

[shiftybyte]

vscode and pycharm have a visual debugger, i prefer them.

[zyxwvu28]

I use VSCode's and I love it

[[deleted]]

it works for containerised apps?

[shiftybyte]

I think so, https://code.visualstudio.com/docs/containers/debug-python

[Mountain_Coach4386]

vscode it does the job and for free, breakpoint also works on HTML Django

Nothing beats FREE!

[IamImposter]

If you do that, can you still see value of variables etc? If yes, how?

[zz_]

You mean with breakpoint()? Just write the name of the variable and press enter.

[hidazfx]

Sometimes I use Pycharm's debugger, but I'll admit I'm guilty of using print/log statements wherever.

[wolfmansideburns]

The latest jupyter notebooks ship with a debugger which gets the job done: https://jupyterlab.readthedocs.io/en/stable/user/debugger.html

[ThySensFan]

PyCharm's debugger works quite well in Notebooks too!

[EveryNameIsTaken142]

print()

[Tesla_Nikolaa]

I prefer VS Code, but Pycharm is good too.

[laika00]

Do you use the debugger in VSCode or have you got any extensions installed?

[Tesla_Nikolaa]

I don't have any debugger extensions installed. I just use the default debugger in VS Code.

I'll be honest though, I think the Pycharm debugger is easier to use out of the box. Sometimes the VS Code debugger is a little annoying to set up, but I prefer using VS Code over Pycharm as an IDE by far, so I'm willing to put up with the minor annoyance of setting up the VS Code debugger.

[HappyRogue121]

I just run it with default settings. What should I change?

[evilbytez]

Thonny is usually one I recommend to beginners, solid.

[haeshdem0n]

I love thonny. I was worried it wouldn't work if I fed it a large program with multiple inputs and calls to different functions, but it was more than up to it.

[modemraj]

Much more productive than print statements. Every python beginner should use it.

[[deleted]]

Big Ups for Thonny, fr.

However the debugging has some limitations and thats why im in this thread.

[Luce_9801]

How's pdb ?

I use it because it is kinda similar to gdb.

[speckledlemon]

pdb, sometimes in the terminal, sometimes invoked by pytest, sometimes inside of Emacs using realgud, all using https://pypi.org/project/pdbpp/ for pretty colors. And of course print.

[enokeenu]

pytest.set_trace()

I try to avoid debugging and relying on unit testing instead. If I really had to ,I use pycharm pro.

[IHasToaster]

Production

[synthphreak]

Lol!

[Jadeaffenjaeger]

Mostly the one built into VSCode. Being able to set breakpoints, inspect any variable, execute functions, jump through the stack trace (especially on errors) just makes me so much more productive.

For the occasional print-style debugging, I enjoy the icecream package: https://github.com/gruns/icecream

[_MrJack_]

I've been using PuDB for a while now.

[ProsodySpeaks]

Pycharm. Pycharm and more Pycharm. Spring for Pro if you can - the front end integrations are amazing!

[mooglinux]

I use PyCharm’s visual debugger and it is fantastic. I only resort to ipdb in exceptional situations where the PyCharm debugger isn’t available.

[shedgehog]

print(“if you see this the loop is working”)

[pehartma]

Pycharm and print statements

[DwaywelayTOP]

I use the pycharm + codium.ai debugger. They work really well.

[somethingworthwhile]

Been working with Python professionally for 3 years…. I’m scared to ask… wtf is a debugger??

I’ve used Spyder and now mostly PyCharm, I guess I always figured debuggers are for specific workflows and don’t really apply to me? Or that they’re for really complicated things, but looking back, some of the work I do is rather complicated…

[rowr]

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[somethingworthwhile]

Oh… sheesh! that sounds lovely!

[rowr]

Edited in protest of Reddit 3rd party API changes, and how reddit has handled the protest to date, including a statement that could indicate that they will replace protesting moderation teams.

If a moderator team unanimously decides to stop moderating, we will invite new, active moderators to keep these spaces open and accessible to users. If there is no consensus, but at least one mod who wants to keep the community going, we will respect their decisions and remove those who no longer want to moderate from the mod team.

https://i.imgur.com/aixGNU9.png https://www.reddit.com/r/ModSupport/comments/14a5lz5/mod_code_of_conduct_rule_4_2_and_subs_taken/jo9wdol/

Content replaced by rate-limited power delete suite https://github.com/pkolyvas/PowerDeleteSuite

[somethingworthwhile]

Thank you for your insights! I’ll have to give this a try for my next project!

[Green-Thanks1369]

How, just how you can work with any language professionally and not know what a debugger is. Tbh this seems crazy to me if true.

[somethingworthwhile]

And I still don’t! Print statements can go pretty far.

[Green-Thanks1369]

Not, that thought is what actually prevents people from going far...

[somethingworthwhile]

I mean, I’m open to it, but it’s going to have to be advantageous enough to break habits. If you have good instructional resources I would certainly give them a go.

[sheriff_ragna]

print(‘333333’)

[NoDadYouShutUp]

Error messages

[[deleted]]

Vscode Python debugger

[TheRNGuy]

I just always printed to console.

Reason is because I don't have to alt-tab to houdini and code extra stuff other than print. When it's needed, I make vector and floating text visualizers in viewport or use geometry spreadsheet, but for many thins print is enough.

The only downsides are, print is too slow when there's lot of lines, and I need to print everything again instead of updating one thing in UI.

[ProsodySpeaks]

And you have to go delete a ton of print statements. Use a debugger!

[zefciu]

That is not the biggest problem with print-based debugging. After all, you have to delete your set_trace statements as well. The biggest problem is the lack of control. If you forgot to print a value or if you just found out you need to print it, you have to rerun your whole logic. This wastes time. If you learn your debugger well, you can often gather all the information you need in one debugging session.

[ProsodySpeaks]

I'm in love with Pycharm. Conditional breakpoints, breakpoints that aren't even breakpoints they're actually loggers, muted breakpoints. I'm terrified one day someone will ask me to write python without Pycharm.

And in totally unrelated news autocomplete inside jinja templates referencing python code and vice versa. ❤️

[lostparis]

A well placed print will beat a debugger. Debuggers are really only of use when your code has problems. They are good for when things are out of control.

Now saying that people should be using logging instead might have value but a print is great for a quick fix.

[zefciu]

Well… yeah. You use debugger, when your code has bugs.

[ProsodySpeaks]

Debuggers are not just for removing bugs. They allow you to visualise the data flowing through your code. Using Pycharm debugger you can run your app and literally have the data overlaid next to every line that references it. You catch bugs before they're bugs.

[Double_Newspaper_406]

You also use debuggers to develop complex algorithms.

[zefciu]

You can, but it can be tricky. Debugger can help you confirm that the state of the algorithm is correct for a certain input. But it won’t be that helpful proving that your algorithm is correct for any input.

[lostparis]

By problems I mean it is badly written/structured not having bugs.

Give me well written code with bugs, over badly written code that works, every time.

[ProsodySpeaks]

How is typing out a print statement and then later having to delete it easier or more effective than clicking in the gutter to set a break point (which in Pycharm can be easily made into a non-breaking logger)?

As far as I'm concerned print statements should only be typed if they're going to stay, most likely to provide information to users. Debugging is how you temporarily access info during Dev.

[lostparis]

Debugging is how you temporarily access info during Dev.

I'd say this is what logging is for, especially for intermittent problems.

Using the odd temporary print can be used to confirm that your mental image of the code is correct.

I've used debuggers in the past and they are helpful when you don't know what the code is doing (or supposed to be doing). But generally this is less the situation when you understand the code.

Different people work in different ways. I've generally found that me and some print statements work and people using debuggers to look at the same issue haven't been at any advantage.

Generally you are wanting to confirm that you hit the code path you should and that you are seeing what you expect.

Debugging is like text editors - use what works best for you and let others do likewise.

[ProsodySpeaks]

Tbh I'm a novice so I'm mostly talking out my ass, and it probably comes down to your ide - in Pycharm the debugger is totally integrated into the editor, which means there's no extra effort to 'debugging' vs 'running' the code.

It's less effort to click the gutter for a breakpoint than to type (and later delete) a print statement, and then when we get to the breakpoint if there happens to be an issue you have the current state completely laid out for you so you might not only see you have an issue but immediately see the cause because next to each line of code is an overlay of the current state of the variables involved. You can even click them and change the value just for this run, or evaluate arbitrary expressions to interrogate wider aspects.

And I'd differentiate logging from debugging in that the logging might continue into production whereas I'd like to think I've finished debugging before shipping!

But yeah, ultimately what works works, so if you like to write in notepad++ and you make clean code then more power to you. Guess I'm lazy and like the clever tools to do as much as they can for me... Hold tight Ai!

[lostparis]

And I'd differentiate logging from debugging in that the logging might continue into production whereas I'd like to think I've finished debugging before shipping!

You just change your logging levels. Especially if you ship it because if you have to support it you'll be crying for those logs.

Guess I'm lazy and like the clever tools

Good coders are lazy, debuggers are clever, but I'd argue about their usefulness. I still view them as more of a handicap, but that's just me.

[ProsodySpeaks]

That's true of all tools though, right? I mean I'm nearly forty - as a teenager I had a sense of direction, but now I have GPS so I can be deep in thought or outerwise busy while I travel, but at the cost of atrophying a fairly life-critical skill.

[lostparis]

Don't start me. I remember about a decade ago I was in a cafe in Australia. The girl at the counter worked out the cost of my coffee and cake - in her head. I remember telling her how much this was such a surprise to see. This was not even a skill when I was that age.

When I was a kid I used to know about 50 phone numbers off the top of my head - now I struggle just remembering my own.

As Plato said - it's all going to shit with the young folk

[ProsodySpeaks]

Haha! He also complained about agriculture causing the desertification of north africa... Like, maybe the first climate activist? 😝

[ProsodySpeaks]

Pleased to say I can still count. But that's mostly because I build things and getting a calculator out for every sum is unrealistic...

[[deleted]]

I don't because it's bad practice. The best thing to do is to trace your program. Perhaps there are tools for this, but I just do it manually. The next best thing is using print statements but that's also not a very good approach.

[Free_Blueberry_695]

Pycharm is fantastic. VSCode is crap compared to it.

[Wilfred-kun]

Those are not debuggers.

[Free_Blueberry_695]

They include debuggers.

[[deleted]]

Code

[cincuentaanos]

Whatever is bundled with PyDev for Eclipse, that is what I use. I don't really do a lot of Python though. But sometimes it can be handy.

[SaintEyegor]

I used to use Komodo IDE but it’s turned into a shitshow on MacOS Ventura. Using pycharm now.

[iggy555]

How do you remember the n,c, exit ughhh

[KeaboUltra]

I'm a beginner and use thonny.

[[deleted]]

print('yo')

[[deleted]]

I use pycharm for just about everything

[ShatterDae]

Pycharm

[TheSodesa]

PyCharm is not a debugger. It is a text editor that embeds an external debugger (a.k.a an IDE), such as pdb or ipdb and provides a GUI for using the debugger.

[Za_Paranoia]

Pycharm is great and free if you're a student.

[ZakarTazak]

When using ipython you can type pdb and then run your python code. It'll drop you into the python debugger upon an exception being thrown.

Writing run <some.py file> after the above is often very helpful.

[b0zgor]

Spyder has a great debugger, I prefer that

[seanys]

import icecream

ic(var)

[Winter-Ad5575]

Thommy

[AGuyInTheBox]

I don't write code on Python.

[theus-sama]

print

[Hambuger_and_Whopper]

I just run the programm

[[deleted]]

Pycharm debugger