Question

假设我有一串数字

"1 2 3 4 5 6"

我想拆分此字符串并将每个数字放入向量中的不同插槽中。什么是最好的方法

Answer 1

使用istringstream将字符串称为流，并使用>>运算符来获取数字。如果字符串包含换行符和制表符，它也会起作用。这是一个例子：

#include <vector>
#include <sstream>  // for istringstream
#include <iostream>  // for cout

using namespace std;  // I like using vector instead of std::vector

int main() 
{
  char *s = "1 2 3 4 5";
  istringstream s2(s);
  vector<int> v;
  int tmp;

  while (s2 >> tmp) {
    v.push_back(tmp);
  }

  // print the vector
  for (vector<int>::iterator it = v.begin(); it != v.end(); it++) {
    cout << *it << endl;
  }

}

Answer 2

#include <iostream>
#include <string>
#include <algorithm>
#include <cstdlib>

std::vector<std::string> StringToVector(std::string const& str, char const delimiter);

int main(){

    std::string str{"1 2     3 4  5 6    "};
    std::vector<std::string> vec{StringToVector(str, ' ')};


    //print the vector
    for(std::string const& item : vec){
        std::cout << "[" << item << "]";
    }


    return EXIT_SUCCESS;
}

std::vector<std::string> StringToVector(std::string const& str, char const delimiter){

    std::vector<std::string> vec;
    std::string element;


    //we are going to loop through each character of the string slowly building an element string.
    //whenever we hit a delimiter, we will push the element into the vector, and clear it to get ready for the next element
    for_each(begin(str),end(str),[&](char const ch){
        if(ch!=delimiter){
            element+=ch;
        }
        else{
            if (element.length()>0){
            vec.push_back(element);
            element.clear();
            }
        }
    });


    //push in the last element if the string does not end with the delimiter
    if (element.length()>0){
        vec.push_back(element);
    }


    return vec;
}

g ++ -std = c ++ 0x -o main main.cpp

这样做的好处是永远不会将空字符串推入向量中你也可以选择你想要的分隔符。
也许你可以写一些其他的：一个用于字符向量，或者分隔符可能是一个字符串？ :)
祝好运！

Answer 3

#include <vector>
#include <string>
#include <sstream>
int str_to_int(const string& str){
    stringstream io;
    int out;
    io<<str;
    io>>out;
    return out;
};

vector<int> Tokenize(string str, string delimiters = " ")
{   
    vector<int> tokens;
    string::size_type nwpos; //position of first non white space, which means it is     first real char
    nwpos = str.find_first_not_of(delimiters, 0); //ignore the whitespace before the first word

    string::size_type pos = str.find_first_of(delimiters, nwpos);

    while (string::npos != pos || string::npos != nwpos)
    {
        // Found a token, add it to the vector.
        tokens.push_back(str_to_int(str.substr(nwpos, pos - nwpos)));
        // Skip delimiters.  Note the "not_of"
        nwpos = str.find_first_not_of(delimiters, pos);
        // Find next "non-delimiter"
        pos = str.find_first_of(delimiters, nwpos);
    }
    return tokens;
};

Answer 4

尝试：

#include <sstream>
#include <string>
#include <algorithm>
#include <iterator>
#include <vector>

int main()
{
    // The data
    std::string data = "1 2 3 4 5 6";

    // data in a stream (this could be a file)
    std::stringstream datastream(data);

    // Copy the data from the stream into a vector.
    std::vector<int>  vec;
    std::copy(std::istream_iterator<int>(datastream), std::istream_iterator<int>(),
              std::back_inserter(vec)
             );


    // We can also copy the vector to the output (or any other stream).
    std::copy(vec.begin(), vec.end(),
              std::ostream_iterator<int>(std::cout, "\n")
             );
}

通过空格将字符串解析为向量

4 个答案: