如何迭代由空格分隔的单词组成的字符串中的单词?

注意,我对C字符串函数或那种字符操作/访问不感兴趣。比起效率,我更喜欢优雅。我当前的解决方案:

#include <iostream>
#include <sstream>
#include <string>

using namespace std;

int main() {
    string s = "Somewhere down the road";
    istringstream iss(s);

    do {
        string subs;
        iss >> subs;
        cout << "Substring: " << subs << endl;
    } while (iss);
}

当前回答

这是我的方法,切割和分割:

string cut (string& str, const string& del)
{
    string f = str;

    if (in.find_first_of(del) != string::npos)
    {
        f = str.substr(0,str.find_first_of(del));
        str = str.substr(str.find_first_of(del)+del.length());
    }

    return f;
}

vector<string> split (const string& in, const string& del=" ")
{
    vector<string> out();
    string t = in;

    while (t.length() > del.length())
        out.push_back(cut(t,del));

    return out;
}

顺便说一下,如果我能做些什么来优化这个。。

其他回答

这是我的版本

#include <vector>

inline std::vector<std::string> Split(const std::string &str, const std::string &delim = " ")
{
    std::vector<std::string> tokens;
    if (str.size() > 0)
    {
        if (delim.size() > 0)
        {
            std::string::size_type currPos = 0, prevPos = 0;
            while ((currPos = str.find(delim, prevPos)) != std::string::npos)
            {
                std::string item = str.substr(prevPos, currPos - prevPos);
                if (item.size() > 0)
                {
                    tokens.push_back(item);
                }
                prevPos = currPos + 1;
            }
            tokens.push_back(str.substr(prevPos));
        }
        else
        {
            tokens.push_back(str);
        }
    }
    return tokens;
}

它适用于多字符分隔符。它防止空令牌进入结果。它使用单个标头。当您不提供分隔符时,它将字符串作为一个标记返回。如果字符串为空,它还会返回一个空结果。不幸的是,它的效率很低,因为存在巨大的std::vector副本,除非您使用C++11进行编译,否则应该使用移动示意图。在C++11中,这段代码应该很快。

下面的代码使用strtok()将字符串拆分为标记,并将标记存储在向量中。

#include <iostream>
#include <algorithm>
#include <vector>
#include <string>

using namespace std;


char one_line_string[] = "hello hi how are you nice weather we are having ok then bye";
char seps[]   = " ,\t\n";
char *token;



int main()
{
   vector<string> vec_String_Lines;
   token = strtok( one_line_string, seps );

   cout << "Extracting and storing data in a vector..\n\n\n";

   while( token != NULL )
   {
      vec_String_Lines.push_back(token);
      token = strtok( NULL, seps );
   }
     cout << "Displaying end result in vector line storage..\n\n";

    for ( int i = 0; i < vec_String_Lines.size(); ++i)
    cout << vec_String_Lines[i] << "\n";
    cout << "\n\n\n";


return 0;
}

短而优雅

#include <vector>
#include <string>
using namespace std;

vector<string> split(string data, string token)
{
    vector<string> output;
    size_t pos = string::npos; // size_t to avoid improbable overflow
    do
    {
        pos = data.find(token);
        output.push_back(data.substr(0, pos));
        if (string::npos != pos)
            data = data.substr(pos + token.size());
    } while (string::npos != pos);
    return output;
}

可以使用任何字符串作为分隔符,也可以与二进制数据一起使用(std::string支持二进制数据,包括空值)

使用:

auto a = split("this!!is!!!example!string", "!!");

输出:

this
is
!example!string
#include <iostream>
#include <vector>
using namespace std;

int main() {
  string str = "ABC AABCD CDDD RABC GHTTYU FR";
  str += " "; //dirty hack: adding extra space to the end
  vector<string> v;

  for (int i=0; i<(int)str.size(); i++) {
    int a, b;
    a = i;

    for (int j=i; j<(int)str.size(); j++) {
      if (str[j] == ' ') {
        b = j;
        i = j;
        break;
      }
    }
    v.push_back(str.substr(a, b-a));
  }

  for (int i=0; i<v.size(); i++) {
    cout<<v[i].size()<<" "<<v[i]<<endl;
  }
  return 0;
}

根据Galik的回答,我做了这个。这大部分都在这里,所以我不必一遍又一遍地写。C++仍然没有原生拆分函数,这真是太疯狂了。特征:

应该很快。容易理解(我认为)。合并空节。使用多个分隔符(例如“\r\n”)很简单

#include <string>
#include <vector>
#include <algorithm>

std::vector<std::string> split(const std::string& s, const std::string& delims)
{
    using namespace std;

    vector<string> v;

    // Start of an element.
    size_t elemStart = 0;

    // We start searching from the end of the previous element, which
    // initially is the start of the string.
    size_t elemEnd = 0;

    // Find the first non-delim, i.e. the start of an element, after the end of the previous element.
    while((elemStart = s.find_first_not_of(delims, elemEnd)) != string::npos)
    {
        // Find the first delem, i.e. the end of the element (or if this fails it is the end of the string).
        elemEnd = s.find_first_of(delims, elemStart);
        // Add it.
        v.emplace_back(s, elemStart, elemEnd == string::npos ? string::npos : elemEnd - elemStart);
    }
    // When there are no more non-spaces, we are done.

    return v;
}