473,587 Members | 2,494 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

Why can't you use varargs and keyword arguments together?

I've always wondered why I can't do:

def foo(a,b,c):
return a,b,c

args = range(2)
foo(*args, c = 2)

When you can do:

foo(*args, **{'c':2})

Whenever I stub my toe on this one, I always just use the second
approach, which seems less readable. As with most things in Python,
I've suspected there's a good reason for it. Having just bumped into
this one again, I thought I'd ask if anyone knows why the first syntax
should not be allowed.

This comes up anyplace you need variable arguments and keyword
arguments together but don't have the keyword arguemnts in a dict. In
this case you are forced to put them in a dict. I don't think anyone
would find that to be more readable.

Thanks and Merry Christmas,
-Sandra

Dec 21 '06 #1
1 1563
On Dec 21, 5:59 pm, Jean-Paul Calderone <exar...@divmod .comwrote:
>You just need to turn things around:
>>def foo(a, b, c):
... return a, b, c
...
>>args = range(2)
>>foo(c=2, *args)
(0, 1, 2)
>>>
You know, I feel like a real shmuck for not trying that...

Thanks!
-Sandra

Dec 22 '06 #2

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

9
4973
by: grid | last post by:
Hi, I have a function which takes a variable number of arguments.It then calls va_start macro to initialize the argument list.But here in my case I have a special builtin va_start provided by the compiler which I use for performance gains.Then the variable arguments are passed to another varargs function which then uses a builtin va_arg macro to get the arguments. Iam getting an error from the compiler in the called function when a local...
10
5108
by: Armando Serrano Lombillo | last post by:
Why does Python give an error when I try to do this: Traceback (most recent call last): File "<pyshell#40>", line 1, in <module> len(object=) TypeError: len() takes no keyword arguments but not when I use a "normal" function: return len(object)
5
3090
by: Gene | last post by:
Hello all. Is the initializing assignment below ANSI standard- conforming? Is there a way to have the prefix parameters to ... type checked in such an assignment? E.g. in this case int x in the typedef matched with int a of foo? Appreciate the help. ------------
6
29508
by: antianti | last post by:
Hello, I have a function that has a variable # of arguments of varying types. int foo(short a, ...) { va_list argp va_start(argp, a); ... va_end(argp);
0
8219
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
0
8349
jinu1996
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...
1
7978
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
0
8221
tracyyun
by: tracyyun | last post by:
Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
0
6629
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...
1
5722
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules. He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms. Adolph will...
1
2364
by: 6302768590 | last post by:
Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
1
1455
muto222
by: muto222 | last post by:
How can i add a mobile payment intergratation into php mysql website.
0
1192
bsmnconsultancy
by: bsmnconsultancy | last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.