目录

pdb

pdb 是 Python 自带的程序包，为 Python 程序提供了一种可交互的源码调试功能。主要特性包括：

• 设置断点
• 单步调试
• 进入函数调试
• 查看当前代码
• 查看栈片段
• 动态修改变量值

pdb 的 Debug 方式

• pdb 可以在源码内直接使用，相当于打断点，import pdb 后，在需要调试的代码处添加写入 pdb.set_trace() 语句即可。

def pushit():

    import pdb

    pdb.set_trace()

    stack.append(raw_input('Enter New String: ').strip())

• 通过命令行参数的形式来进行调试，EG.

python -m pdb stack_demo.py

• 在 Python 交互环境中调试

>>> import pdb

>>> import mymodule

>>> pdb.run(‘mymodule.test()’)

pdb 的调试指令

示例

stack_demo.py : 一个 Python 实现的 栈 数据结构

stack = []

def pushit():

    #import pdb

    #pdb.set_trace()

    stack.append(raw_input('Enter New String: ').strip())

def popit():

    if len(stack) == 0:

        print "Cannot pop from an empty stack!"

    else:

        print 'Remove [', `stack.pop()`, ']'

def viewstack():

        print stack

CMDs = {'u':pushit, 'o':popit, 'v':viewstack}

def showmenu():

    pr = """

    p(U)sh

    p(O)p

    (V)iew

    (Q)uit

    Enter choice: """

    while True:

        while True:

            try:

                choice = raw_input(pr).strip()[0].lower()

            except (EOFError, KeyboardInterrupt, IndexError):

                choice = 'q'

            print '\nYou picked: [%s]' % choice

            if choice not in 'uovq':

                print 'Invalid option, try again'

            else:

                break

        if choice == 'q':

            break

        CMDs[choice]()

if __name__ == '__main__':

    showmenu()

通过命令行参数的形式来进行调试

In [2]: !python -m pdb stack_demo.py

> d:\development\python27\workspace\stack_demo.py(1)<module>()

-> stack = []            # 这种方式会从第一条语句开始进入调试

(Pdb) b 7                # 空白行或注释不能打断点

*** Blank or comment

(Pdb) b 8                # 在 codeline == 8 处打上断点

Breakpoint 1 at d:\development\python27\workspace\stack_demo.py:8

(Pdb) n                  # 下一行

> d:\development\python27\workspace\stack_demo.py(3)<module>()

-> def pushit():

(Pdb) n                  # 下一行，并且跳过函数内的语句

> d:\development\python27\workspace\stack_demo.py(10)<module>()

-> def popit():

(Pdb) l                  # 列出下面的代码

  3     def pushit():

  4

  5         #import pdb

  6         #pdb.set_trace()

  7

  8 B->     stack.append(raw_input('Enter New String: ').strip())

  9

 10     def popit():

 11         if len(stack) == 0:

 12             print "Cannot pop from an empty stack!"

 13         else:

(Pdb) n

Enter New String: 'jmilkfan'

--Return--

> d:\development\python27\workspace\stack_demo.py(8)pushit()->None

-> stack.append(raw_input('Enter New String: ').strip())

(Pdb) w                  # 打印当前位置

  d:\development\python27\lib\bdb.py(400)run()

-> exec cmd in globals, locals

  <string>(1)<module>()

  d:\development\python27\workspace\stack_demo.py(49)<module>()

-> showmenu()

  d:\development\python27\workspace\stack_demo.py(46)showmenu()

-> CMDs[choice]()

> d:\development\python27\workspace\stack_demo.py(8)pushit()->None

-> stack.append(raw_input('Enter New String: ').strip())

(Pdb) p stack                  # 输出一个变量的值

["'jmilkfan'"]

(Pdb) !stack = ["fanguiju"]    # 改变一个变量的值

(Pdb) p stack

['fanguiju']

(Pdb) c                        # 继续往下执行

        p(U)sh

        p(O)p

        (V)iew

        (Q)uit

        Enter choice: q

You picked: [q]

The program finished and will be restarted

> d:\development\python27\workspace\stack_demo.py(1)<module>()

-> stack = []

(Pdb) q                       # 退出调试

• 在源码内直接使用

In [8]: run stack_demo.py

        p(U)sh

        p(O)p

        (V)iew

        (Q)uit

        Enter choice: u

You picked: [u]

> d:\development\python27\workspace\stack_demo.py(8)pushit()

-> stack.append(raw_input('Enter New String: ').strip())    # 开始进入调试，该语句的前一条语句为 pdb.set_trace()

(Pdb) l

  3     def pushit():

  4

  5         import pdb

  6         pdb.set_trace()

  7

  8  ->     stack.append(raw_input('Enter New String: ').strip())

  9

 10     def popit():

 11         if len(stack) == 0:

 12             print "Cannot pop from an empty stack!"

 13         else:

(Pdb) j 16            # 不能跳转到还没有执行过的代码行

*** Jump failed: line 16 comes after the current code block

(Pdb) j 3

> d:\development\python27\workspace\stack_demo.py(3)pushit()

-> def pushit():

(Pdb) s              # 进入一个函数内部

> d:\development\python27\workspace\stack_demo.py(6)pushit()

-> pdb.set_trace()

(Pdb) s              # 还可以进入到调用函数的内部

--Call--

> d:\development\python27\lib\pdb.py(1250)set_trace()

-> def set_trace():

(Pdb) c              # 继续执行代码

> d:\development\python27\workspace\stack_demo.py(8)pushit()

-> stack.append(raw_input('Enter New String: ').strip())

(Pdb) r              # 执行代码直到从当前函数返回

Enter New String: 'jmilkfan'

--Return--

> d:\development\python27\workspace\stack_demo.py(8)pushit()->None

-> stack.append(raw_input('Enter New String: ').strip())

(Pdb) l

 25             (V)iew

 26             (Q)uit

 27

 28             Enter choice: """

 29

 30  ->     while True:

 31             while True:

 32                 try:

 33                     choice = raw_input(pr).strip()[0].lower()

 34                 except (EOFError, KeyboardInterrupt, IndexError):

 35                     choice = 'q'

(Pdb) c

        p(U)sh

        p(O)p

        (V)iew

        (Q)uit

        Enter choice: u

You picked: [u]

> d:\development\python27\workspace\stack_demo.py(8)pushit()

-> stack.append(raw_input('Enter New String: ').strip())

(Pdb) s

--Call--

> d:\development\python27\lib\site-packages\win_unicode_console\raw_input.py(71)raw_input()

-> def raw_input(prompt=""):

(Pdb) p pr

'\n\tp(U)sh\n\tp(O)p\n\t(V)iew\n\t(Q)uit\n\t\n\tEnter choice: '

(Pdb) n

        p(U)sh

        p(O)p

        (V)iew

        (Q)uit

        Enter choice: v

> d:\development\python27\workspace\stack_demo.py(37)showmenu()

-> print '\nYou picked: [%s]' % choice

(Pdb) n

You picked: [v]

> d:\development\python27\workspace\stack_demo.py(38)showmenu()

-> if choice not in 'uovq':

(Pdb) n

> d:\development\python27\workspace\stack_demo.py(41)showmenu()

-> break

(Pdb) n

> d:\development\python27\workspace\stack_demo.py(44)showmenu()

-> if choice == 'q':

(Pdb) n

> d:\development\python27\workspace\stack_demo.py(46)showmenu()

-> CMDs[choice]()

(Pdb) n

[u"'jmilkfan'", u"'fanguiju'", u"'fanguiju'"]

> d:\development\python27\workspace\stack_demo.py(30)showmenu()

-> while True:

(Pdb) n

> d:\development\python27\workspace\stack_demo.py(31)showmenu()

-> while True:

(Pdb) n

> d:\development\python27\workspace\stack_demo.py(32)showmenu()

-> try:

(Pdb) n

> d:\development\python27\workspace\stack_demo.py(33)showmenu()

-> choice = raw_input(pr).strip()[0].lower()

(Pdb) n

        p(U)sh

        p(O)p

        (V)iew

        (Q)uit

        Enter choice: v

> d:\development\python27\workspace\stack_demo.py(37)showmenu()

-> print '\nYou picked: [%s]' % choice

(Pdb) c

You picked: [v]

[u"'jmilkfan'", u"'fanguiju'", u"'fanguiju'"]

        p(U)sh

        p(O)p

        (V)iew

        (Q)uit

        Enter choice: 0

IPython 自带的 Debug 工具 ipdb

基本用法跟 pdb 一样，优点在于很 IPython 结合使用能更方便的完成一个功能，也更加清晰。

In [1]: run -d stack_demo.py

Breakpoint 1 at d:\development\python27\workspace\stack_demo.py:1

NOTE: Enter 'c' at the ipdb>  prompt to continue execution.

> d:\development\python27\workspace\stack_demo.py(1)<module>()

1---> 1 stack = []

      2

      3 def pushit():

      4

      5     stack.append(raw_input('Enter New String: ').strip())

ipdb> h

Documented commands (type help <topic>):

========================================

EOF    bt         cont      enable  jump  pdef    psource  run      unt

a      c          continue  exit    l     pdoc    q        s        until

alias  cl         d         h       list  pfile   quit     step     up

args   clear      debug     help    n     pinfo   r        tbreak   w

b      commands   disable   ignore  next  pinfo2  restart  u        whatis

break  condition  down      j       p     pp      return   unalias  where

Miscellaneous help topics:

==========================

exec  pdb

Undocumented commands:

======================

ll  longlist  retval  rv

ipdb>