Python Debugger (pdb) is a powerful tool for debugging Python code. It allows you to execute your code step by step, set breakpoints, and inspect the values of variables at any given point. pdb provides several shortcuts and convenience features to make the debugging process more efficient and effective. In this blog post, we will explore some of the commonly used shortcuts and convenience features offered by pdb.

1. Step through code execution

The most basic functionality of pdb is to step through the code and execute it line by line. This can be done using the s or step command. It allows you to understand how your code is being executed and track any unexpected behavior.

import pdb

def my_function():
    x = 5
    y = 10
    z = x + y
    return z

pdb.set_trace()
result = my_function()
print(result)

2. Set breakpoints

Breakpoints are markers that pause the execution of the code at a specific line. This allows you to inspect the values of variables and analyze the code at that particular point. pdb provides two convenient commands to set breakpoints:

• b or break: Set a breakpoint at the current line of execution.
• b <linenum>: Set a breakpoint at the specified line number.

import pdb

def my_function():
    x = 5
    y = 10
    pdb.set_trace()  # Set a breakpoint at this line
    z = x + y
    return z

result = my_function()
print(result)

3. Inspect variable values

pdb allows you to inspect the values of variables at any point during the execution of your code. The p or pp command is used for this purpose. It prints the value of a variable to the console.

import pdb

def my_function():
    x = 5
    y = 10
    pdb.set_trace()
    z = x + y
    return z

result = my_function()
pdb.p(result)  # Print the value of `result`

4. Continue execution

Once a breakpoint is hit, you can continue the execution of the code using the c or continue command. This will resume the code execution until the next breakpoint or until the program finishes.

import pdb

def my_function():
    x = 5
    y = 10
    pdb.set_trace()
    z = x + y
    return z

result = my_function()
print(result)
pdb.c()  # Continue execution until the end of the program

5. Debugger commands

pdb provides a range of additional commands to help you debug your code effectively. Some commonly used commands include:

• n or next: Execute the next line of code.
• l or list: Show the current line of code and the surrounding lines.
• q or quit: Quit the debugger and terminate the program.
• h or help: Show a list of available commands and their descriptions.

These commands can be used in the pdb command line interface to interact with the debugger during the debugging process.

Conclusion

In this blog post, we explored some of the useful shortcuts and convenience features offered by pdb, Python’s built-in debugger. By using these shortcuts, you can navigate through your code, set breakpoints, inspect variable values, and continue execution with ease. Understanding and utilizing these features can greatly enhance your ability to debug and troubleshoot Python code effectively.