• Paolo Invernizzi <paolo.invernizzi srlabs.it> Sep 07 2010
• "Simen kjaeraas" <simen.kjaras gmail.com> Sep 07 2010
• bearophile <bearophileHUGS lycos.com> Sep 07 2010

Paolo Invernizzi <paolo.invernizzi srlabs.it> writes:

Hi all,

What's the best way to find an element into an array, drop it and shrink the
array inplace, in D2?

Thanks in advance, Paolo

"Simen kjaeraas" <simen.kjaras gmail.com> writes:

Paolo Invernizzi <paolo.invernizzi srlabs.it> wrote:

 Hi all,

 What's the best way to find an element into an array, drop it and shrink  
 the array inplace, in D2?

 Thanks in advance, Paolo


T extract( T )( ref T[] haystack, const T element ) {
     auto loc = indexOf( haystack, element );
     T result = haystack[loc];
     haystack = haystack[0..loc] ~ haystack[loc+1..$];
     return result;
}

Not tested, but should work.

-- 
Simen

bearophile <bearophileHUGS lycos.com> writes:

Paolo Invernizzi:
 What's the best way to find an element into an array, drop it and shrink  
 the array inplace, in D2?


Inside the module std.array there is a commented out function that allows to
remove items. I don't know why it is commented out, maybe there is some bug.

You can find the index with the indexOf().
Then if your items don't have a postblit (and you can test for that), then you
may just need std.c.string.memmove to shift the items.
If the items are structs with a postblit, then I presume the best thing you can
do is to copy each item in a normal loop.
After that "static if", you decrease the array length by 1, and return the item
saved in a temporary variable.

------------------------------

Simen kjaeraas:
 T extract( T )( ref T[] haystack, const T element ) {
      auto loc = indexOf( haystack, element );
      T result = haystack[loc];
      haystack = haystack[0..loc] ~ haystack[loc+1..$];
      return result;
 }


It's not in-place, as requested by Paolo.

Bye,
bearophile