'Rcpp' Interface to 'sparsepp'

Provides interface to 'sparsepp' - fast, memory efficient hash map. It is derived from Google's excellent 'sparsehash' implementation. We believe 'sparsepp' provides an unparalleled combination of performance and memory usage, and will outperform your compiler's unordered_map on both counts. Only Google's 'dense_hash_map' is consistently faster, at the cost of much greater memory usage (especially when the final size of the map is not known in advance).

CRAN_Status_Badge License

Check original sparsepp repository and write-up which compares hashmap implementations.


Use sparsepp from another package

To use C++ code from sparsepp:

  1. In DESCRIPTION, add LinkingTo: sparsepp.
  2. In the C++ file, add: #include <sparsepp/spp.h>

Simple example

#include <sparsepp/spp.h>
using spp::sparse_hash_map;
sparse_hash_map<string, int> smap;

Defining custom hash function

#include <iostream>
#include <functional>
#include <string>
#include <sparsepp/spp.h>
using std::string;
struct Person 
    bool operator==(const Person &o) const 
    { return _first == o._first && _last == o._last}
    string _first;
    string _last;
namespace std
    // inject specialization of std::hash for Person into namespace std 
    // ---------------------------------------------------------------- 
    struct hash<Person>
        std::size_t operator()(Person const &p) const
            std::size_t seed = 0;
            spp::hash_combine(seed, p._first);
            spp::hash_combine(seed, p._last);
            return seed;
int main()
    // As we have defined a specialization of std::hash() for Person,  
    // we can now create sparse_hash_set or sparse_hash_map of Persons 
    // ---------------------------------------------------------------- 
    spp::sparse_hash_set<Person> persons = { { "John""Galt" }
                                             { "Jane""Doe" } };
    for (auto& p: persons)
        std::cout << p._first << ' ' << p._last << '\n';



  • update to upstream v1.22


  • updated to upstream v1.21

Reference manual

It appears you don't have a PDF plugin for this browser. You can click here to download the reference manual.


1.22 by Dmitriy Selivanov, 3 years ago

https://github.com/greg7mdp/sparsepp, https://github.com/dselivanov/r-sparsepp

Report a bug at https://github.com/dselivanov/r-sparsepp/issues

Browse source code at https://github.com/cran/sparsepp

Authors: Gregory Popovitch [aut, cph] , Google Inc [aut, cph] , Dmitriy Selivanov [cre]

Documentation:   PDF Manual  

BSD_3_clause + file LICENSE license

Suggests Rcpp

See at CRAN