conditional breakpoint using pdb

Question

Sounds like I'm missing something extremely simple, I'm trying to set a breakpoint in my python code using:

if(some condition):
        pdb.set_trace()

My error in the code comes after a large number of iterations..difficult to debug using print etc. I am able to print stuff when the condition hits but I would like to set brk-pt.

--EDIT--

Actual code:

import pdb
if (node_num == 16):
    print node_num
    pdb.set_trace()

Answer 1

I see you found your solution Sanjay. But for those who arrived here looking for a means to set a conditional breakpoint with pdb read on:

Instead of hard coding conditions such as if node_num == 16:, run pdb in interactive mode. Sample code:

import pdb

for node_num in range(50):
  do_something(node_num)
...

In the shell start the script in debug mode using -m pdb:

[rick@rolled ~]$ python -m pdb abc.py
> /home/dcadm/abc.py(1)<module>()
-> import pdb
(Pdb) l
  1  -> import pdb
  2
  3     for node_num in range(50) :
  4       foo = 2**node_num
[EOF]
(Pdb) b 4, node_num > 4
Breakpoint 1 at /home/dcadm/abc.py:4
(Pdb) c
> /home/dcadm/abc.py(4)<module>()
-> foo = 2**node_num
(Pdb) node_num 
5
(Pdb)

The pdb shell command b 4, node_num > 4 breaks at line 4 when node_num is greater than 4.