When I was young and didn't know much about programming, I remember someone saying to me "functions can return only one value." I also remember thinking to myself, "then I'm going to be the guy to write a language that allows you to return multiple values."
I was naive back then, to say the least.
Of course, there are plenty of ways to return more than one value from a function. In languages with pointers, like C and C++, you can pass in an "out" parameter to functions, and have the function dereference that pointer, setting values to it. In languages with
ADTs, you can return say, a
Point which would then encompass two or more variables. In many of these, you might have to do that via an out parameter as well.
Of course, there are arrays and structs and components in Coldfusion. And there are string lists in just about any language (some of which may be implemented via arrays).
But I always wanted to do something like this:
var_one, var_two, var_three = some_method()
Fortunately for me, Ruby allows you to do just that. It is implemented as an array (to my knowledge), but the syntax is so elegant you'd never know it:
def some_function
return 1, 2, 3
end
one, two, three = some_function
puts one #outputs "1"
puts two #outputs "2"
puts three #outputs "3"
Pretty sweet if you ask me.
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You can do this in perl, too. Very handy.
sub getname() {
@ret = qw(Ryan Stille M);
return @ret;
}
($first,$last,$middle) = getname();
Posted by
Ryan Stille
on Jan 29, 2007 at 08:48 AM UTC - 6 hrs
Cool. I haven't played around with perl much. I think once I had to fix a bug in an application that used it, and that was about it.
For those that don't know, I think the qw() turns each token separated by a space into a word. Is that right?
Posted by
Sam
on Jan 29, 2007 at 09:19 AM UTC - 6 hrs
Pretty close. qw() is a shortcut for creating arrays out of a list of words without having to use quotes or commas. Could also have been written like
@ret = ('Ryan', 'Stille', 'M');
or
$ret[0] = 'Ryan';
$ret[1] = 'Stille';
$ret[2] = 'M';
Posted by
Ryan Stille
on Jan 29, 2007 at 09:23 AM UTC - 6 hrs
You can do this with Python as well. The syntax is nearly identical. (actually one line shorter)
def some_function():
return 1,2,3
one, two, three = some_function()
print one
print two
print three
Posted by brian
on Jan 29, 2007 at 10:32 AM UTC - 6 hrs
I know because of the web it didn't show up, but the whitespace you'll see in brian's example if you were to view source is significant.
Basically, you'll need to indent the return statement (He did, you just can't see it on the web).
Maybe I need to do something to preserve all whitespace in the comments, not just the crlf.
Posted by
Sam
on Jan 29, 2007 at 11:33 AM UTC - 6 hrs
Also, my understanding is that Ruby and Python are very similar to each other, so I wouldn't be surprised to learn that other code we see in each of them may be almost identical.
Posted by
Sam
on Jan 29, 2007 at 11:39 AM UTC - 6 hrs
how can return more one value in c language
with our using structure some thing like that
get me as erly as possible
try to explain with example
Posted by chandu
on Oct 29, 2007 at 01:34 PM UTC - 6 hrs
Chandu - You would pass in any number of pointers, dereference them and set the values they point to. Ex:
int addTwoNumbersTwice(int w, int x, int y, int z, int *sum1, int *sum2)
{
*sum1 = w + x;
*sum2 = y + z;
}
As you can see, it's not really returning the values, it is setting them on the outside. You would call it like:
int *sum1, *sum2;
addTwoNumbersTwice(1,2,3,4,sum1,sum2);
I didn't test. I'll leave that to you.
Posted by
Sam
on Oct 29, 2007 at 01:49 PM UTC - 6 hrs
