Re: Replacing array_slice

On Tue, Jul 17, 2018 at 6:24 AM Gabriel Caruso <carusogabriel34@gmail.com> wrote: > > Hi Levi, thanks for bringing this discussion. > >> Recently I've been scrutinizing array_slice. It's been painful. >> >> For instance, $preserve_keys is totally ignored for string >> keys. >> This was undocumented until Christoph integrated it 2-3 days ago >> (thanks, cmb). However, this is really not a good design decision: why >> have a parameter that is called preserve_keys if the data >> gets the >> final say, especially since there isn't any technical requirement for >> this? >> >> Here's another "fun" behavior: negative offsets whose absolute values >> are larger than the size of the array (eg the array has 3 elements and >> you pass an offset of -5) will shift the window to begin at zero >> instead of truncating the out-of-range values (which is what happens >> on the positive side). >> >> And another: $length is a length when it's a positive >> number, but >> it's an offset from the end when it's negative. You could perhaps >> convince me that when length is positive it's an offset from the >> $offset parameter. However, if you look at the design of >> slicing >> functions in other languages (eg Python, Ruby, JavaScript) they take >> beginning and ending offsets, not a beginning offset and a length. >> >> And another: it always iterates from the beginning of the array even >> if you are only interested in the last half (somewhat common for >> various algorithms that split things in half). >> >> Fixing array_slice would probably do more harm than good at >> this >> stage. Instead I would like to provide an alternative function that >> does not have all this baggage, and will have decent performance much >> of the time. The best ideas I have for names are not that great: >> >> - array_real_slice? >> - array_slice2? >> >> We could also split it into 2 functions, one that preserves keys and >> one that doesn't, instead of using a parameter. Any ideas there? >> >> -- >> PHP Internals - PHP Runtime Development Mailing List >> To unsubscribe, visit: http://www.php.net/unsub.php > > > A while ago I come up with this discussion in my Twitter, not with a new function, but with a > new "operator": > https://twitter.com/carusogabriel/status/974610078807613443 > > What do you think? > > Thanks, I think slicing can potentially be a good feature, but there is a lot more design space for this than there is for just adding a new function. Given the other things I have on my plate right now I don't want to start another feature; someone else is welcome to try. "chop" in some other languages effectively means removing leading or trailing members - this would be misleading here. array_extract has no relation to extract, which might be confusing. It might be okay. What about array_subslice for a name? People might initially be curious about having both array_slice and array_subslice, which will hopefully lead them to reading documentation that array_subslice is preferred, but that there are no current plans to remove array_slice.