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How do you use print statements effectively for debugging, including showing variable names alongside values? How do you use the traceback module to capture and format a full exception traceback as a string, useful for logging? How do you use the timeit module to accurately measure a small code snippet's execution time? How do you use cProfile to identify which functions are consuming the most time in a larger program? How do assert statements work for debugging, and why should they NOT be relied upon for production input validation? How do you use Python's built-in 'warnings' module to surface deprecated or risky code paths during debugging? How would you use the 'faulthandler' module to diagnose a program that crashes with a segmentation fault, typically from a C extension? How do you use memory_profiler (or tracemalloc from the standard library) to identify a memory leak's source in a Python application? How would you use the 'logging' module's exception logging (logger.exception()) INSIDE an except block to automatically capture the full traceback? How do you use pdb's post-mortem debugging mode to inspect a program's state exactly at the point where an unhandled exception occurred?
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How do you use the built-in pdb debugger to pause execution at a specific line?

Beginner

Answer

Insert 'import pdb; pdb.set_trace()' (or the shorter 'breakpoint()' in Python 3.7+) at the line where you want execution to pause — this drops you into an interactive debugger prompt where you can inspect variables, step through code, and evaluate expressions.
def calculate_total(items):
    breakpoint()  # execution pauses here, drops into pdb
    return sum(item.price for item in items)
Real-world example Pausing mid-function to inspect why a calculated total doesn't match the expected value.

Common follow-ups: What are the basic pdb commands for stepping through code: 'n', 's', 'c', and 'l'?

Exception Handling
All 15 Debugging & Profiling questions