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digitalmars.D - array.remove(int), similar to aa.remove(key)

reply Lionello Lunesu <lio lunesu.remove.com> writes:
array.remove(int) could simply replace [i] with [$-1] and decrement the 
length.

I need this quite a lot and it gets tiresome writing the same 'for' over 
and over. Furthermore, like I've mentioned in the title: since AA's have 
it, it makes sense to add it to normal arrays as well.

L.
May 24 2006
next sibling parent reply Oskar Linde <oskar.lindeREM OVEgmail.com> writes:
Lionello Lunesu skrev:

 array.remove(int) could simply replace [i] with [$-1] and decrement the 
 length.
 
 I need this quite a lot and it gets tiresome writing the same 'for' over 
 and over. Furthermore, like I've mentioned in the title: since AA's have 
 it, it makes sense to add it to normal arrays as well.


Since arrays are ordered, it is not clear that array.remove(int) should be

array[i] = array[$-1], array.length = array.length -1;

rather than:

array = array[0..$i-1] ~ array[i+1..$];


Note: if you want to implement array.remove(int) by yourself, it is 
trivial (untested code):

template remove(ArrTy, IntTy) {
	static assert(is(IntTy : int));
	void remove(ArrTy arr, IntTy ix) {
		arr[ix] = arr[$-1];
		arr.length = arr.length - 1;
	}
}

and use it such as:

char[] t = "abc".dup;
assert(t.remove(1) == "ac");

Regards,

Oskar
May 24 2006
next sibling parent Oskar Linde <oskar.lindeREM OVEgmail.com> writes:
Ough, some mistakes.

Oskar Linde skrev:

 Lionello Lunesu skrev:

 array.remove(int) could simply replace [i] with [$-1] and decrement 
 the length.

 I need this quite a lot and it gets tiresome writing the same 'for' 
 over and over. Furthermore, like I've mentioned in the title: since 
 AA's have it, it makes sense to add it to normal arrays as well.


 
 Since arrays are ordered, it is not clear that array.remove(int) should be
 
 array[i] = array[$-1], array.length = array.length -1;
 
 rather than:
 
 array = array[0..$i-1] ~ array[i+1..$];


$i is a typo, should be i.


 
 
 Note: if you want to implement array.remove(int) by yourself, it is 
 trivial (untested code):
 
 template remove(ArrTy, IntTy) {
     static assert(is(IntTy : int));
     void remove(ArrTy arr, IntTy ix) {
         arr[ix] = arr[$-1];
         arr.length = arr.length - 1;
     }
 }
 
 and use it such as:
 
 char[] t = "abc".dup;
 assert(t.remove(1) == "ac");


The template function above doesn't return anything, so this should of 
course be:

char[] t = "abc".dup;
t.remove(1);
assert(t == "ac");

/Oskar
May 24 2006
prev sibling parent Lionello Lunesu <lio lunesu.remove.com> writes:
Oskar Linde wrote:

 Lionello Lunesu skrev:

 array.remove(int) could simply replace [i] with [$-1] and decrement 
 the length.

 I need this quite a lot and it gets tiresome writing the same 'for' 
 over and over. Furthermore, like I've mentioned in the title: since 
 AA's have it, it makes sense to add it to normal arrays as well.


 
 Since arrays are ordered, it is not clear that array.remove(int) should be
 
 array[i] = array[$-1], array.length = array.length -1;
 
 rather than:
 
 array = array[0..$i-1] ~ array[i+1..$];


OK, so there could be two removes, ordered and unordered.


 Note: if you want to implement array.remove(int) by yourself, it is 
 trivial (untested code):
 
 template remove(ArrTy, IntTy) {
     static assert(is(IntTy : int));
     void remove(ArrTy arr, IntTy ix) {
         arr[ix] = arr[$-1];
         arr.length = arr.length - 1;
     }
 }


That's what I did, and it's the code I end up coding/copy-pasting 
whenever I need it. Nice touch though, that static assert.

L.
May 24 2006
prev sibling parent Chris Nicholson-Sauls <ibisbasenji gmail.com> writes:
Lionello Lunesu wrote:

 array.remove(int) could simply replace [i] with [$-1] and decrement the 
 length.
 
 I need this quite a lot and it gets tiresome writing the same 'for' over 
 and over. Furthermore, like I've mentioned in the title: since AA's have 
 it, it makes sense to add it to normal arrays as well.
 
 L.


I ended up moving all my personal "always copy-pasted template functions" into
my personal 
library (Cashew) so I didn't have to paste them into anything anymore.  ;) 
Might consider 
doing the same.  If Cashew's ArrayUtils module suits you, I can just post it
for you.

Interface doc'd at:
http://www.codemeu.com:81/~pontiff/projects/cashew/docs/ArrayUtils.html

Code at:
http://www.codemeu.com:81/~pontiff/projects/cashew/cashew.zip

-- Chris Nicholson-Sauls
May 25 2006