Questions tagged [equal-range]
25 questions
5
votes
3 answers
How to implement equal range "iterator"
how would one implement generic (aka works for multimap, sorted vector ...)
equal range iterator? By this I mean it is an iterator that is a pair of iterators (begin and end of a particular equal_range)
Motivation for this is that I have a multimap…
NoSenseEtAl
- 28,205
- 28
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- 277
3
votes
2 answers
Why unordered_map::equal_range upper_bound returns end if a key is less than first map element
I've noticed that unordered_map::equal_range upper_bound (first) returns end if the passed key is less than map's first one
#include
#include
Alexander Maximov
- 77
- 7
3
votes
2 answers
C++ operations on values given by multiset::equal_range
I'm trying to write a program that is taking 1000 random numbers from 0 to 9 and then counting how many times each number appeared:
srand(time(NULL));
multiset M;//multiset that contains 1000 random numbers from 0 to 9
for (int i =…
Ania
- 450
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3
votes
3 answers
std::equal_range not working with strucutre having operator< defined
I am trying to use std::equal_range with the structure below I have compilation error saying that error: no match for ‘operator<’ .
struct MyFoo {
int v_;
string n_;
bool operator<(int v) const
{ return v_ < v;}
};
…
Abruzzo Forte e Gentile
- 14,423
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3
votes
1 answer
Boost multi_index_container partial index search based on results of partial_index_search
To illustrate my question, I copied below code from the "Phonebook" example of Boost help doc.
struct phonebook_entry
{
std::string family_name;
std::string given_name;
std::string ssn;
std::string phone_number;
}
And I can do a partial…
Michael
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2
votes
2 answers
Do we really need two overload for operator () in functor?
Look at this example (from cppreference):
#include
#include
#include
struct S
{
int number;
char name;
// note: name is ignored by this comparison operator
bool operator< ( const S& s ) const {…
Test
- 564
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- 12
2
votes
0 answers
How equal_range is making use of heterogeneous comparison?
How is Comp{} in std::equal_range triggering the Compare operation? Is Comp{} indicating a R-Value being created?
#include
#include
#include
struct S
{
int number;
char name;
// note: name is…
Test
- 564
- 3
- 12
2
votes
3 answers
Find equal range for container with string with prefix
I am having 2 iterators range_begin,range_end, which are my container. I need to find all string which start with char prefix.
Here is my code:
template
pair FindStartsWith(
RandomIt range_begin, RandomIt…
Станислав Китаев
- 147
- 9
1
vote
1 answer
can i use equal_range to get range of values or end of container?
i know that equal_range(k) gets me range of values:
starting with k or element greater than k or end and
finishing with element greater than k or end.
i wanna modify this behaviour to give me only range of values :
starting with k or end
finishing…
ahmed allam
- 377
- 2
- 15
1
vote
1 answer
Rcpp: sum multimap values by key using equal range
Below I have a code snippet that encapsulates an issue I am having.
What I am trying to do would be trivial in R, but is much more difficult in Rcpp. I am just trying aggregate values according to their respective keys. In this example, I am just…
R_user1233
- 450
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- 9
1
vote
0 answers
Erasing an equal_range iterator
I've got a pair of iterators:
pair ::iterator, multimap::iterator> range;
range = m_DirectoryMap.equal_range(obj);
That pair holds duplicated elements in a MultiMap - e.g. there is 1 object that has 2 more…
Calihog
- 135
- 2
- 11
1
vote
3 answers
equal_range and 2 overloads have no legal conversion for 'this' pointer
Here is this simple code
#include
OoDeLally
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1
vote
1 answer
find vs equal_range and performance
I am doing some tests with find, equal_range and my own binary search functions and I am having some trouble understanding why equal_range takes so long when compared with a find.
I have a sorted vector and I time the duration of the search…
André Moreira
- 1,669
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0
votes
0 answers
How can I change a visual studio code that creates a thematic map using equal ranges method, into creating thematic map using Natural breaks?
I am trying to use visual studio to create a thematic map that reads the
data in my Mapinfo table " Neighborhoods" and show them in a map by dividing the
data into equal ranges, and to do that I am using this code:
using System;
using…
0
votes
1 answer
Using `std::equal_range` with `boost::transform_iterator`
Say I have a struct of Items that I'm storing in an std::set and sorting like so:
struct Position
{
int x;
int y;
}
struct Item
{
std::string id;
Position position;
// NOTE: only `position` should matter for equality
…
Addy
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