What value should be passed to make a function use the default argument value?

[LaundroMat]

Suppose I have this function:

def f(var=1):
return var*2

What value do I have to pass to f() if I want it to evaluate var to 1?
I know that f() will return 2, but what if I absolutely want to pass a
value to f()? "None" doesn't seem to work..

Thanks in advance.

[Lawrence Oluyede]

LaundroMat <La*****@gmail. comwrote:

What value do I have to pass to f() if I want it to evaluate var to 1?
I know that f() will return 2, but what if I absolutely want to pass a
value to f()? "None" doesn't seem to work..

I don't know if I understand correctly here but:

def f(v=1):
return v * 2

f() returns 2
f(1) returns 2 too

v = 1
f(v) returns 2 too

What do you mean?

--
Lawrence - http://www.oluyede.org/blog
"Nothing is more dangerous than an idea
if it's the only one you have" - E. A. Chartier

[Fredrik Lundh]

LaundroMat wrote:

Suppose I have this function:

def f(var=1):
return var*2

What value do I have to pass to f() if I want it to evaluate var to 1?
I know that f() will return 2, but what if I absolutely want to pass a
value to f()?

f(1)

"None" doesn't seem to work..

None is an object.

</F>

[Tim Chase]

def f(var=1):

return var*2

What value do I have to pass to f() if I want it to evaluate var to 1?
I know that f() will return 2, but what if I absolutely want to pass a
value to f()? "None" doesn't seem to work..

>>def f(var=1):

.... return var*2
....

>>f()

2

>>f(0.5)

1.0

>>f(123)

246

>>f('hello')

'hellohello'
I'm not sure I follow your problem...what' s stopping you from
passing a value?

-tkc

[Larry Bates]

LaundroMat wrote:

Suppose I have this function:

def f(var=1):
return var*2

What value do I have to pass to f() if I want it to evaluate var to 1?
I know that f() will return 2, but what if I absolutely want to pass a
value to f()? "None" doesn't seem to work..

Thanks in advance.

The answer is don't pass any value.

print f()

will print 2

-Larry Bates

[Thomas Jollans]

On Tue, 03 Oct 2006 13:16:57 -0700, "LaundroMat " <La*****@gmail. comlet
this slip:

Suppose I have this function:

def f(var=1):
return var*2

What value do I have to pass to f() if I want it to evaluate var to 1?
I know that f() will return 2, but what if I absolutely want to pass a
value to f()? "None" doesn't seem to work..

Thanks in advance.

a) if you feel that your program needs to pass a value, fix the program.

b)

>>def f(v=1):

.... return v*2
....

>>f()

2

>>f(1)

2

>>f(*[1])

2

>>f(*[])

2

>>>

*[list] is the reverse of def f(*args)

--
Thomas Jollans alias free-zombie

[Stan Graves]

LaundroMat wrote:

Suppose I have this function:

def f(var=1):
return var*2

What value do I have to pass to f() if I want it to evaluate var to 1?
I know that f() will return 2, but what if I absolutely want to pass a
value to f()? "None" doesn't seem to work..

What about this?

>>def f(var=None):

.... if var == None:
.... var = 1
.... return 2*var
....

>>f()

2

>>f(3)

6

>>a=4
f(a)

8

>>b=None
f(b)

2

>>>

--Stan Graves

[Bruno Desthuilliers]

LaundroMat a écrit :

Suppose I have this function:

def f(var=1):
return var*2

What value do I have to pass to f() if I want it to evaluate var to 1?

I know that f() will return 2, but what if I absolutely want to pass a
value to f()? "None" doesn't seem to work..

Have you tried f(1) ?

[Rob De Almeida]

LaundroMat wrote:

Suppose I have this function:

def f(var=1):
return var*2

What value do I have to pass to f() if I want it to evaluate var to 1?
I know that f() will return 2, but what if I absolutely want to pass a
value to f()? "None" doesn't seem to work..

If you *absolutely* want to pass a value and you don't know the default
value (otherwise you could just pass it):

>>import inspect
v = inspect.getargs pec(f)[3][0] # first default value
f(v)

2

[Antoon Pardon]

On 2006-10-03, LaundroMat <La*****@gmail. comwrote:

Suppose I have this function:

def f(var=1):
return var*2

What value do I have to pass to f() if I want it to evaluate var to 1?
I know that f() will return 2, but what if I absolutely want to pass a
value to f()? "None" doesn't seem to work..

Thanks in advance.

One possible way to do what I think you want is to code as follows:

class Default (object):
pass

def f(var=Default):
if var is Default:
var = 1
return var * 2

--
Antoon Pardon