Use C++-Iterators on Python-List with the Python/C API? -

-

is possible use tools needing iterators , function-pointer module <algorithm> on pyobjects ?

the concrete problem want solve (it constructed learn it):

  • i have huge list of ids stored in python-list
  • now want perform std::binary_search on list, using module written in c++

one way access python-list c-array, constructing vector (which uses pointers/ not copy), doing binary_search , export array pyobject.

would possible?

well, binary search isn't complicated, why don't code 1 based on range of indices instead of iterators? believe list conforms sequence protocol of python, should pretty easy.

if want use binary_search() algorithm learning experience, there possibility create stl-style iterators on top of python sequence. need pointer sequence , index create random-access iterator. if want to, can transparently convert python objects in list according id type (some integer type, guess).

struct iterator {     // typedefs required compliant stl-style iterators     typedef pyobject* value_type;      iterator(pyobject* seqeunce, py_ssize_t position):         m_sequence(sequence), m_position(position)     {         assert(pysequence_check(m_sequence));         assert(m_position >= 0);         assert(m_position <= pysequence_getsize(m_sequence));     }     value_type operator*() const     {         assert(m_position < pysequence_getsize(m_sequence));         return pysequence_getitem(m_sequence, m_position);     }     iterator& operator++()     {         assert(m_position <= pysequence_getsize(m_sequence));         ++m_position;         return *this;     }     iterator& operator+=(size_t l)     {         m_position += l;         return *this;     } };

i haven't compiled , forgot few parts, guess idea. init 2 iterators, 1 offset of 0 , 1 offset of size of container , give binary_search().


Comments

Post a Comment

Popular posts from this blog

Perl - how to grep a block of text from a file -

-
it can in xml or text format. how in general grep block of text in perl? <track type="ws"> <range> <rangestart>0</rangestart> <rangeend>146.912</rangeend> <locationindex>0</locationindex> <propertyindex>0</propertyindex> </range> </track> <track type="ps" id="1"> <range> <rangestart>0</rangestart> <rangeend>146.912</rangeend> <locationindex>1</locationindex> <propertyindex>1</propertyindex> </range> </track> i want grep type="ps" , till </range> . one solution open file, read line line , match block. open(fh, "file.txt"); foreach $line (<fh>) { if ($line =~ m/type="cc"(.*?)<\/range>/) { print $1; } } but there more optimal solution without reading file line l
Read more

delphi - How to remove all the grips on a coolbar if I have several coolbands? -

-
Image
if set mycoolbar.fixedorder true,only grip on first band hidden. well,if use delphi 7 create vcl forms application,then put coolbar on , create 3 coolbans hold other controls,only grip , top coolbands can hidden setting mycoolbar.fixedorder:=true. i've uploaded picture make things clear. you got fixedorder property wrong. fixed property not allow bands rearranged if set true . setting property of coolbar true keep user changing bands order @ runtime, user can still move , resize bands. can give advice can do, actual solution problem, well, have wait answer. my advice use 3 coolbars in row , setting "fixedorder" property true , bandborderstyle bsnone . way grip hidden on of them. about property, it's not bug of ide, actual preference of property.
Read more

javascript - Animating array of divs; only the final element is modified -

-
this baffling me @ moment. i'm experienced programmer looking throw bit of surprise fiancee on countdown page our wedding. desired effect simulated confetti falling behind main page. setup follows: i have array of divs in javascript. each div absolutely positioned on page. have interval set updates every 50 or milliseconds. on each tick, run loop on array of divs, , calculations , update positions. problem problem having, however, though can see divs created, stored array, , modified (in case, each has slight randomized rotation) during initialization phase, once tick update position starts, div stored in whatever last slot of array gets position updated. tried hard-coding each div index testing purposes, strictly last element update position. upon printing current "left" , "top" style values each div before , after calculations shows value has been changed, no visible change noticeable. here's basic code: javascript var container;
Read more