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copied!<p>As a guess, Python strings are reference counted immutable strings, so that no strings are copied around in the Python code, while C++ <code>std::string</code> is a mutable value type, and is copied at the smallest opportunity.</p> <p>If the goal is fast splitting, then one would use constant time substring operations, which means only <em>referring</em> to parts of the original string, as in Python (and Java, and C#…).</p> <p>The C++ <code>std::string</code> class has one redeeming feature, though: it is <em>standard</em>, so that it can be used to pass strings safely and portably around where efficiency is not a main consideration. But enough chat. Code -- and on my machine this is of course faster than Python, since Python's string handling is implemented in C which is a subset of C++ (he he):</p> <pre><code>#include <iostream> #include <string> #include <sstream> #include <time.h> #include <vector> using namespace std; class StringRef { private: char const* begin_; int size_; public: int size() const { return size_; } char const* begin() const { return begin_; } char const* end() const { return begin_ + size_; } StringRef( char const* const begin, int const size ) : begin_( begin ) , size_( size ) {} }; vector<StringRef> split3( string const& str, char delimiter = ' ' ) { vector<StringRef> result; enum State { inSpace, inToken }; State state = inSpace; char const* pTokenBegin = 0; // Init to satisfy compiler. for( auto it = str.begin(); it != str.end(); ++it ) { State const newState = (*it == delimiter? inSpace : inToken); if( newState != state ) { switch( newState ) { case inSpace: result.push_back( StringRef( pTokenBegin, &*it - pTokenBegin ) ); break; case inToken: pTokenBegin = &*it; } } state = newState; } if( state == inToken ) { result.push_back( StringRef( pTokenBegin, &*str.end() - pTokenBegin ) ); } return result; } int main() { string input_line; vector<string> spline; long count = 0; int sec, lps; time_t start = time(NULL); cin.sync_with_stdio(false); //disable synchronous IO while(cin) { getline(cin, input_line); //spline.clear(); //empty the vector for the next line to parse //I'm trying one of the two implementations, per compilation, obviously: // split1(spline, input_line); //split2(spline, input_line); vector<StringRef> const v = split3( input_line ); count++; }; count--; //subtract for final over-read sec = (int) time(NULL) - start; cerr << "C++ : Saw " << count << " lines in " << sec << " seconds." ; if (sec > 0) { lps = count / sec; cerr << " Crunch speed: " << lps << endl; } else cerr << endl; return 0; } //compiled with: g++ -Wall -O3 -o split1 split_1.cpp -std=c++0x </code></pre> <p>Disclaimer: I hope there aren't any bugs. I haven't tested the functionality, but only checked the speed. But I think, even if there is a bug or two, correcting that won't significantly affect the speed.</p>

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