Python Learning note 012--pdb debugging

1 description

The PDB is a Python-brought package that provides an interactive source code debugging function for Python programs.

Key features include setting breakpoints, stepping through debugging, entering function debugging, viewing current code, viewing stack fragments, dynamically changing the values of variables, etc.

Debug function:

Allows the program to step through, observing intermediate results

Specify breakpoints can be set for specific position observation

2 Debugging commands

Full command	Shorthand command	Describe
Args	A	Print the parameters of the current function
Break	B	Set breakpoints
Clear	Cl	Clear breakpoints
Condition	No	Set conditional breakpoints
Continue	C or cont	Continue running, knowing that a breakpoint was encountered or the script ended
Disable	No	disabling breakpoints
Enable	No	Enable breakpoints
Help	H	View PDB Help
Ignore	No	Ignore Breakpoint
Jump	J	Jump to a specified number of rows run
List	L	List script lists
Next	N	Executes the next statement, encountering a function that does not enter its interior
P	P	Print variable values, or you can
Quit	Q	Exit PDB
Return	R	Run until function returns
Tbreak	No	Set a temporary breakpoint, break only once
Step	S	Executes the next statement, encounters a function into its internal
where	W	See where you are
!	No	Executing statements in the PDB

Attention:

1: Enter enter directly, will execute the previous command;

2: Enter a command that the PDB does not know, and the PDB will execute it as a Python statement in the current environment;

3 Example 3.1 Example 1 (test code)

1 Import PDB 2 " AAA " 3 pdb.set_trace () 4 " BBB " 5 " CCC " 6 final = a + B + c7print(final)

Run

>/home/tarena/Desktop/t.py (4) <module>()b ="BBB"(PDB) n>/home/tarena/Desktop/t.py (5) <module>()c ="CCC"(PDB)>/home/tarena/Desktop/t.py (6) <module>()Final = a + B +C (Pdb)>/home/tarena/Desktop/t.py (7) <module>()-Print(Final) (PDB) AAABBBCCC--return-->/home/tarena/Desktop/t.py (7) <module> ()None-Print(Final) (PDB)

To start Debugging:

Run the script directly, will stay at Pdb.set_trace () , pdb.set_trace () function : From the pdb.set_trace () position to enter the debug state, The code that follows the statement is stepping .

Select N+enter to perform the current statement. After you press N+enter for the first time, you can press ENTER directly to repeat the previous debug command.

Importpdbpdb.set_trace ()defA (n):Print(n + 1)    Print(n + 2)    Print(n + 3)    Print(n + 4)    Print(n + 5)    Print(n + 6)defb (n):Print('b', N) A (n+ 1)    Print("B End")defC (): X= 100B (x+ 100) C ()

Run

>/home/tarena/Desktop/t.py (4) <module>()def  A (n):(Pdb) n>/home/tarena/Desktop/t.py ( <module>()def>/home/tarena/Desktop/t.py (+) <module>()def >/home/tarena/Desktop/t.py (+) <module>()200202203204205206207 b   End --return-->/home/tarena/Desktop/t.py (<module>),None,

3.2 Example 2 (code debugging)

Detailed code

https://www.ibm.com/developerworks/cn/linux/l-cn-pythondebugger/

Https://docs.python.org/3.6/library/pdb.html

Python Learning note 012--pdb debugging