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
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<---
其他回答
谢谢@Jairo Abdiel Toribio Cisneros。它对我有效，但您的函数返回一些空元素。因此，对于没有空的返回，我编辑了以下内容：
std::vector<std::string> split(std::string str, const char* delim) {
std::vector<std::string> v;
std::string tmp;
for(std::string::const_iterator i = str.begin(); i <= str.end(); ++i) {
if(*i != *delim && i != str.end()) {
tmp += *i;
} else {
if (tmp.length() > 0) {
v.push_back(tmp);
}
tmp = "";
}
}
return v;
}
使用：
std::string s = "one:two::three";
std::string delim = ":";
std::vector<std::string> vv = split(s, delim.c_str());
如果您希望按某些字符分割字符串，可以使用
#include<iostream>
#include<string>
#include<vector>
#include<iterator>
#include<sstream>
#include<string>
using namespace std;
void replaceOtherChars(string &input, vector<char> ÷rs)
{
const char divider = dividers.at(0);
int replaceIndex = 0;
vector<char>::iterator it_begin = dividers.begin()+1,
it_end= dividers.end();
for(;it_begin!=it_end;++it_begin)
{
replaceIndex = 0;
while(true)
{
replaceIndex=input.find_first_of(*it_begin,replaceIndex);
if(replaceIndex==-1)
break;
input.at(replaceIndex)=divider;
}
}
}
vector<string> split(string str, vector<char> chars, bool missEmptySpace =true )
{
vector<string> result;
const char divider = chars.at(0);
replaceOtherChars(str,chars);
stringstream stream;
stream<<str;
string temp;
while(getline(stream,temp,divider))
{
if(missEmptySpace && temp.empty())
continue;
result.push_back(temp);
}
return result;
}
int main()
{
string str ="milk, pigs.... hot-dogs ";
vector<char> arr;
arr.push_back(' '); arr.push_back(','); arr.push_back('.');
vector<string> result = split(str,arr);
vector<string>::iterator it_begin= result.begin(),
it_end= result.end();
for(;it_begin!=it_end;++it_begin)
{
cout<<*it_begin<<endl;
}
return 0;
}
这是一个顶级答案的扩展。它现在支持设置返回元素的最大数量N。字符串的最后一位将在第N个元素中结束。MAXELEMENTS参数是可选的，如果设置为默认值0，它将返回无限数量的元素。：-）
.h:
class Myneatclass {
public:
static std::vector<std::string>& split(const std::string &s, char delim, std::vector<std::string> &elems, const size_t MAXELEMENTS = 0);
static std::vector<std::string> split(const std::string &s, char delim, const size_t MAXELEMENTS = 0);
};
.cpp：
std::vector<std::string>& Myneatclass::split(const std::string &s, char delim, std::vector<std::string> &elems, const size_t MAXELEMENTS) {
std::stringstream ss(s);
std::string item;
while (std::getline(ss, item, delim)) {
elems.push_back(item);
if (MAXELEMENTS > 0 && !ss.eof() && elems.size() + 1 >= MAXELEMENTS) {
std::getline(ss, item);
elems.push_back(item);
break;
}
}
return elems;
}
std::vector<std::string> Myneatclass::split(const std::string &s, char delim, const size_t MAXELEMENTS) {
std::vector<std::string> elems;
split(s, delim, elems, MAXELEMENTS);
return elems;
}
没有Boost，没有字符串流，只有标准的C库与std:：string和std:：list:C库函数配合使用，便于分析，C++数据类型便于内存管理。
空白被认为是换行符、制表符和空格的任意组合。空白字符集由wschars变量建立。
#include <string>
#include <list>
#include <iostream>
#include <cstring>
using namespace std;
const char *wschars = "\t\n ";
list<string> split(const string &str)
{
const char *cstr = str.c_str();
list<string> out;
while (*cstr) { // while remaining string not empty
size_t toklen;
cstr += strspn(cstr, wschars); // skip leading whitespace
toklen = strcspn(cstr, wschars); // figure out token length
if (toklen) // if we have a token, add to list
out.push_back(string(cstr, toklen));
cstr += toklen; // skip over token
}
// ran out of string; return list
return out;
}
int main(int argc, char **argv)
{
list<string> li = split(argv[1]);
for (list<string>::iterator i = li.begin(); i != li.end(); i++)
cout << "{" << *i << "}" << endl;
return 0;
}
Run:
$ ./split ""
$ ./split "a"
{a}
$ ./split " a "
{a}
$ ./split " a b"
{a}
{b}
$ ./split " a b c"
{a}
{b}
{c}
$ ./split " a b c d "
{a}
{b}
{c}
{d}
split的尾部递归版本（本身分裂为两个函数）。除了将字符串推入列表之外，所有对变量的破坏性操作都消失了！
void split_rec(const char *cstr, list<string> &li)
{
if (*cstr) {
const size_t leadsp = strspn(cstr, wschars);
const size_t toklen = strcspn(cstr + leadsp, wschars);
if (toklen)
li.push_back(string(cstr + leadsp, toklen));
split_rec(cstr + leadsp + toklen, li);
}
}
list<string> split(const string &str)
{
list<string> out;
split_rec(str.c_str(), out);
return out;
}
这个答案将字符串放入字符串向量中。它使用boost库。
#include <boost/algorithm/string.hpp>
std::vector<std::string> strs;
boost::split(strs, "string to split", boost::is_any_of("\t "));
