how to define a function from a string using python

Question

this is my code :

a = 
'''def fun():

    print 'bbb'
'''
eval(a)

fun()

but it shows error :

Traceback (most recent call last):
  File "c.py", line 8, in <module>
    eval(a)
  File "<string>", line 1
    def fun():
      ^
SyntaxError: invalid syntax

so what can i do ,

thanks

Answer 1

eval() with a string argument is only for expressions. If you want to execute statements, use exec:

exec """def fun():
  print 'bbb'
"""

But before you do that, think about whether you really need dynamic code or not. By far most things can be done without.