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

是的,我看了所有30个例子。

我找不到一个适用于多字符分隔符的split版本,所以这里是我的:

#include <string>
#include <vector>

using namespace std;

vector<string> split(const string &str, const string &delim)
{   
    const auto delim_pos = str.find(delim);

    if (delim_pos == string::npos)
        return {str};

    vector<string> ret{str.substr(0, delim_pos)};
    auto tail = split(str.substr(delim_pos + delim.size(), string::npos), delim);

    ret.insert(ret.end(), tail.begin(), tail.end());

    return ret;
}

可能不是最有效的实现,但它是一个非常简单的递归解决方案,只使用<string>和<vector>。

啊,它是用C++11编写的,但这段代码没有什么特别之处,因此您可以很容易地将其改编为C++98。

其他回答

我的实施可以是另一种解决方案:

std::vector<std::wstring> SplitString(const std::wstring & String, const std::wstring & Seperator)
{
    std::vector<std::wstring> Lines;
    size_t stSearchPos = 0;
    size_t stFoundPos;
    while (stSearchPos < String.size() - 1)
    {
        stFoundPos = String.find(Seperator, stSearchPos);
        stFoundPos = (stFoundPos == std::string::npos) ? String.size() : stFoundPos;
        Lines.push_back(String.substr(stSearchPos, stFoundPos - stSearchPos));
        stSearchPos = stFoundPos + Seperator.size();
    }
    return Lines;
}

测试代码:

std::wstring MyString(L"Part 1SEPsecond partSEPlast partSEPend");
std::vector<std::wstring> Parts = IniFile::SplitString(MyString, L"SEP");
std::wcout << L"The string: " << MyString << std::endl;
for (std::vector<std::wstring>::const_iterator it=Parts.begin(); it<Parts.end(); ++it)
{
    std::wcout << *it << L"<---" << std::endl;
}
std::wcout << std::endl;
MyString = L"this,time,a,comma separated,string";
std::wcout << L"The string: " << MyString << std::endl;
Parts = IniFile::SplitString(MyString, L",");
for (std::vector<std::wstring>::const_iterator it=Parts.begin(); it<Parts.end(); ++it)
{
    std::wcout << *it << L"<---" << std::endl;
}

测试代码的输出:

The string: Part 1SEPsecond partSEPlast partSEPend
Part 1<---
second part<---
last part<---
end<---

The string: this,time,a,comma separated,string
this<---
time<---
a<---
comma separated<---
string<---

这里有一个拆分函数:

是通用的使用标准C++(无增强)接受多个分隔符忽略空标记(可以轻松更改)模板<typename T>矢量<T>拆分(常量T&str,常量T&分隔符){向量<T>v;typename T::size_type start=0;自动位置=str.find_first_of(分隔符,开始);而(pos!=T::npos){if(pos!=开始)//忽略空标记v.template_back(str,start,pos-start);开始=位置+1;pos=str.find_first_of(分隔符,开始);}if(start<str.length())//忽略尾随分隔符v.template_back(str,start,str.length()-start);//添加字符串的剩余部分返回v;}

示例用法:

    vector<string> v = split<string>("Hello, there; World", ";,");
    vector<wstring> v = split<wstring>(L"Hello, there; World", L";,");

我喜欢将boost/regex方法用于此任务,因为它们为指定拆分条件提供了最大的灵活性。

#include <iostream>
#include <string>
#include <boost/regex.hpp>

int main() {
    std::string line("A:::line::to:split");
    const boost::regex re(":+"); // one or more colons

    // -1 means find inverse matches aka split
    boost::sregex_token_iterator tokens(line.begin(),line.end(),re,-1);
    boost::sregex_token_iterator end;

    for (; tokens != end; ++tokens)
        std::cout << *tokens << std::endl;
}

获取Boost!:-)

#include <boost/algorithm/string/split.hpp>
#include <boost/algorithm/string.hpp>
#include <iostream>
#include <vector>

using namespace std;
using namespace boost;

int main(int argc, char**argv) {
    typedef vector < string > list_type;

    list_type list;
    string line;

    line = "Somewhere down the road";
    split(list, line, is_any_of(" "));

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

    return 0;
}

此示例给出了输出-

Somewhere
down
the
road

这是我写的一个函数,帮助我做了很多事情。它在为WebSocket做协议时帮助了我。

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

vector<string> split ( string input , string split_id ) {
  vector<string> result;
  int i = 0;
  bool add;
  string temp;
  stringstream ss;
  size_t found;
  string real;
  int r = 0;
    while ( i != input.length() ) {
        add = false;
        ss << input.at(i);
        temp = ss.str();
        found = temp.find(split_id);
        if ( found != string::npos ) {
            add = true;
            real.append ( temp , 0 , found );
        } else if ( r > 0 &&  ( i+1 ) == input.length() ) {
            add = true;
            real.append ( temp , 0 , found );
        }
        if ( add ) {
            result.push_back(real);
            ss.str(string());
            ss.clear();
            temp.clear();
            real.clear();
            r = 0;
        }
        i++;
        r++;
    }
  return result;
}

int main() {
    string s = "S,o,m,e,w,h,e,r,e, down the road \n In a really big C++ house.  \n  Lives a little old lady.   \n   That no one ever knew.    \n    She comes outside.     \n     In the very hot sun.      \n\n\n\n\n\n\n\n   And throws C++ at us.    \n    The End.  FIN.";
    vector < string > Token;
    Token = split ( s , "," );
    for ( int i = 0 ; i < Token.size(); i++)    cout << Token.at(i) << endl;
    cout << endl << Token.size();
    int a;
    cin >> a;
    return a;
}