Python debugging with PDB

Simple Debug Python Program 

You can also debug a program in Python like Gcc/gdb, as long as the PDB module is introduced when you run the Python program (assuming that the program you are debugging is named d.py):

$ VI d.py#!/usr/bin/pythondef Main ():        i, sum = 1, 0 for        I in xrange (+):                sum = sum + i        print sumif __name __ = = ' __main__ ':        Main () $ python-m pdb d.py

After running the above command, enter the following interface, you can enter GDB-like command to change the program execution process:

$ python-m pdb 1.py> d.py (3) () def main ():(PDB)

List shows the most recent code snippet for the program:

(Pdb) List  1  #!/usr/bin/python  2  3  ->def Main ():  4  i, sum = 1, 0  5 for  I In xrange:  6  sum = sum + i  7  print sum  8  9  If __name__ = = ' __main__ ':  Main () [EOF]

Next or N executes the next line of code:

(Pdb) next> d.py (9) (), if __name__ = = ' __main__ ':

Set a breakpoint on line 6th with break:

(PDB) Break D.py:6breakpoint 1 at D.py:6 (PDB) List  1  #!/usr/bin/python  2  3  def main ():  4  I, sum = 1, 0  5  ->for i in xrange (+):  6 bsum = sum + i  7  print sum  8  9  if __name __ = = ' __main__ ': ten  Main () [EOF]

If you want to set breakpoints at the function:

(PDB) Break D.maind.py:3 (PDB) List  1  #!/usr/bin/python  2  3 bdef Main ():  4  ->i, sum = 1, 0  5 for  i in xrange (+):  6  sum = sum + i  7  print sum  8  9  If __name__ = = ' __main__ ': Ten  Main () [EOF]

You can also add conditions to breakpoints, such as setting conditions only when sum > 50 breaks:

(Pdb) Break d.py:6, sum > 50Breakpoint 1 at d.py:6

If you want to see the value of a variable, you can print it with the PP command:

(PDB) step> d.py (5) Main (), for I in xrange (:(pdb) pp SUM0

The PDB module can be used directly in the program, after the import PDB pdb.set_trace ():

#!/usr/bin/pythonimport Pdbdef Main ():        i, sum = 1, 0 for        I in xrange (+):                sum = sum + i        pdb.set_trace () 
   print sumif __name__ = = ' __main__ ':        Main ()

This allows the program to run as long as it is running./d.py can be run directly to print sum:

$ ./d.py> d.py (9) Main (), print sum (Pdb)

Summarize

Command	Use
Break or B	Set breakpoints
Continue or C	Continue to execute the program
List or L	View the code snippet for the current row
Step or S	Enter function
Return or R	Executes the code until it returns from the current function
Exit or Q	Abort and exit
Next or N	Executes the next line
Pp	Print the value of a variable
Help	Help

Python debugging with PDB