Function arguments [was: help]

[Steve Holden]

pierre-yves guido wrote:

hello (I hope my english is not so bad),

Your English is quite good. In future, though, please try to make your
subject line say a bit more about the problem - we *all* need help!

I'm doing a training course and I'm a newbie in Python. My problem :
I have a form, and when I click, I make an update. But all the parameters
are all required to make the update. So I'd like to put in my code something
like [optional]...

My code (simplyfied) :

prg.ev_ind_update(wf_pk_ev_ind=wf_pk_ev_ind,wf_fon ction=wf_fonction,wf_nom=wf_nom)

and so, when I put nothing in wf_nom, it put me that error :"the parameter
wf_nom...was omitted from the request...". But sometimes, wf_nom is not
required !

Thanks to help a poor young boy

When you define a function or a method (using the def statement) you can
specify default values for arguments. A simple example:

>>def fun(a, b=3):

... return a*b
...

>>fun(3)

9

>>fun(7)

21

>>fun(7, 4)

28

>>fun(a=7)

21

>>fun(a=3, b=12)

36

>>fun(b=99)

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: fun() takes at least 1 non-keyword argument (0 given)

>>>

You can see several things here:

1. When you call a function you do not *have* to give thte names of the
arguments - they can be matched by position.

2. When you define a function you can specify a default value for one or
more arguments (these argument have to appear *after* the ones for which
no default is defined)

3. If you don't provide a value for an argument that has no default then
you will receive an exception, which normally results in a traceback.

Hope this helps. Welcome to Python, and its friendly community.

regards
Steve
--
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