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
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;
}
我用这个分隔符分隔字符串。第一个将结果放入预先构建的向量中，第二个返回新向量。
#include <string>
#include <sstream>
#include <vector>
#include <iterator>
template <typename Out>
void split(const std::string &s, char delim, Out result) {
std::istringstream iss(s);
std::string item;
while (std::getline(iss, item, delim)) {
*result++ = item;
}
}
std::vector<std::string> split(const std::string &s, char delim) {
std::vector<std::string> elems;
split(s, delim, std::back_inserter(elems));
return elems;
}
请注意，此解决方案不会跳过空令牌，因此下面将找到4项，其中一项为空：
std::vector<std::string> x = split("one:two::three", ':');
如果您喜欢使用boost，但希望使用整个字符串作为分隔符（而不是之前提出的大多数解决方案中的单个字符），可以使用boost_split_iterator。
示例代码包括方便的模板：
#include <iostream>
#include <vector>
#include <boost/algorithm/string.hpp>
template<typename _OutputIterator>
inline void split(
const std::string& str,
const std::string& delim,
_OutputIterator result)
{
using namespace boost::algorithm;
typedef split_iterator<std::string::const_iterator> It;
for(It iter=make_split_iterator(str, first_finder(delim, is_equal()));
iter!=It();
++iter)
{
*(result++) = boost::copy_range<std::string>(*iter);
}
}
int main(int argc, char* argv[])
{
using namespace std;
vector<string> splitted;
split("HelloFOOworldFOO!", "FOO", back_inserter(splitted));
// or directly to console, for example
split("HelloFOOworldFOO!", "FOO", ostream_iterator<string>(cout, "\n"));
return 0;
}
我这样做是因为我需要一种简单的方法来分割字符串和基于c的字符串。。。希望其他人也能发现它很有用。此外，它不依赖令牌，您可以使用字段作为分隔符，这是我需要的另一个键。
我相信可以做一些改进，以进一步提高其优雅度，请尽一切努力
StringSplitter.hpp：
#include <vector>
#include <iostream>
#include <string.h>
using namespace std;
class StringSplit
{
private:
void copy_fragment(char*, char*, char*);
void copy_fragment(char*, char*, char);
bool match_fragment(char*, char*, int);
int untilnextdelim(char*, char);
int untilnextdelim(char*, char*);
void assimilate(char*, char);
void assimilate(char*, char*);
bool string_contains(char*, char*);
long calc_string_size(char*);
void copy_string(char*, char*);
public:
vector<char*> split_cstr(char);
vector<char*> split_cstr(char*);
vector<string> split_string(char);
vector<string> split_string(char*);
char* String;
bool do_string;
bool keep_empty;
vector<char*> Container;
vector<string> ContainerS;
StringSplit(char * in)
{
String = in;
}
StringSplit(string in)
{
size_t len = calc_string_size((char*)in.c_str());
String = new char[len + 1];
memset(String, 0, len + 1);
copy_string(String, (char*)in.c_str());
do_string = true;
}
~StringSplit()
{
for (int i = 0; i < Container.size(); i++)
{
if (Container[i] != NULL)
{
delete[] Container[i];
}
}
if (do_string)
{
delete[] String;
}
}
};
StringSplitter.cpp：
#include <string.h>
#include <iostream>
#include <vector>
#include "StringSplit.hpp"
using namespace std;
void StringSplit::assimilate(char*src, char delim)
{
int until = untilnextdelim(src, delim);
if (until > 0)
{
char * temp = new char[until + 1];
memset(temp, 0, until + 1);
copy_fragment(temp, src, delim);
if (keep_empty || *temp != 0)
{
if (!do_string)
{
Container.push_back(temp);
}
else
{
string x = temp;
ContainerS.push_back(x);
}
}
else
{
delete[] temp;
}
}
}
void StringSplit::assimilate(char*src, char* delim)
{
int until = untilnextdelim(src, delim);
if (until > 0)
{
char * temp = new char[until + 1];
memset(temp, 0, until + 1);
copy_fragment(temp, src, delim);
if (keep_empty || *temp != 0)
{
if (!do_string)
{
Container.push_back(temp);
}
else
{
string x = temp;
ContainerS.push_back(x);
}
}
else
{
delete[] temp;
}
}
}
long StringSplit::calc_string_size(char* _in)
{
long i = 0;
while (*_in++)
{
i++;
}
return i;
}
bool StringSplit::string_contains(char* haystack, char* needle)
{
size_t len = calc_string_size(needle);
size_t lenh = calc_string_size(haystack);
while (lenh--)
{
if (match_fragment(haystack + lenh, needle, len))
{
return true;
}
}
return false;
}
bool StringSplit::match_fragment(char* _src, char* cmp, int len)
{
while (len--)
{
if (*(_src + len) != *(cmp + len))
{
return false;
}
}
return true;
}
int StringSplit::untilnextdelim(char* _in, char delim)
{
size_t len = calc_string_size(_in);
if (*_in == delim)
{
_in += 1;
return len - 1;
}
int c = 0;
while (*(_in + c) != delim && c < len)
{
c++;
}
return c;
}
int StringSplit::untilnextdelim(char* _in, char* delim)
{
int s = calc_string_size(delim);
int c = 1 + s;
if (!string_contains(_in, delim))
{
return calc_string_size(_in);
}
else if (match_fragment(_in, delim, s))
{
_in += s;
return calc_string_size(_in);
}
while (!match_fragment(_in + c, delim, s))
{
c++;
}
return c;
}
void StringSplit::copy_fragment(char* dest, char* src, char delim)
{
if (*src == delim)
{
src++;
}
int c = 0;
while (*(src + c) != delim && *(src + c))
{
*(dest + c) = *(src + c);
c++;
}
*(dest + c) = 0;
}
void StringSplit::copy_string(char* dest, char* src)
{
int i = 0;
while (*(src + i))
{
*(dest + i) = *(src + i);
i++;
}
}
void StringSplit::copy_fragment(char* dest, char* src, char* delim)
{
size_t len = calc_string_size(delim);
size_t lens = calc_string_size(src);
if (match_fragment(src, delim, len))
{
src += len;
lens -= len;
}
int c = 0;
while (!match_fragment(src + c, delim, len) && (c < lens))
{
*(dest + c) = *(src + c);
c++;
}
*(dest + c) = 0;
}
vector<char*> StringSplit::split_cstr(char Delimiter)
{
int i = 0;
while (*String)
{
if (*String != Delimiter && i == 0)
{
assimilate(String, Delimiter);
}
if (*String == Delimiter)
{
assimilate(String, Delimiter);
}
i++;
String++;
}
String -= i;
delete[] String;
return Container;
}
vector<string> StringSplit::split_string(char Delimiter)
{
do_string = true;
int i = 0;
while (*String)
{
if (*String != Delimiter && i == 0)
{
assimilate(String, Delimiter);
}
if (*String == Delimiter)
{
assimilate(String, Delimiter);
}
i++;
String++;
}
String -= i;
delete[] String;
return ContainerS;
}
vector<char*> StringSplit::split_cstr(char* Delimiter)
{
int i = 0;
size_t LenDelim = calc_string_size(Delimiter);
while(*String)
{
if (!match_fragment(String, Delimiter, LenDelim) && i == 0)
{
assimilate(String, Delimiter);
}
if (match_fragment(String, Delimiter, LenDelim))
{
assimilate(String,Delimiter);
}
i++;
String++;
}
String -= i;
delete[] String;
return Container;
}
vector<string> StringSplit::split_string(char* Delimiter)
{
do_string = true;
int i = 0;
size_t LenDelim = calc_string_size(Delimiter);
while (*String)
{
if (!match_fragment(String, Delimiter, LenDelim) && i == 0)
{
assimilate(String, Delimiter);
}
if (match_fragment(String, Delimiter, LenDelim))
{
assimilate(String, Delimiter);
}
i++;
String++;
}
String -= i;
delete[] String;
return ContainerS;
}
示例：
int main(int argc, char*argv[])
{
StringSplit ss = "This:CUT:is:CUT:an:CUT:example:CUT:cstring";
vector<char*> Split = ss.split_cstr(":CUT:");
for (int i = 0; i < Split.size(); i++)
{
cout << Split[i] << endl;
}
return 0;
}
将输出：
这是一实例cst环
int main(int argc, char*argv[])
{
StringSplit ss = "This:is:an:example:cstring";
vector<char*> Split = ss.split_cstr(':');
for (int i = 0; i < Split.size(); i++)
{
cout << Split[i] << endl;
}
return 0;
}
int main(int argc, char*argv[])
{
string mystring = "This[SPLIT]is[SPLIT]an[SPLIT]example[SPLIT]string";
StringSplit ss = mystring;
vector<string> Split = ss.split_string("[SPLIT]");
for (int i = 0; i < Split.size(); i++)
{
cout << Split[i] << endl;
}
return 0;
}
int main(int argc, char*argv[])
{
string mystring = "This|is|an|example|string";
StringSplit ss = mystring;
vector<string> Split = ss.split_string('|');
for (int i = 0; i < Split.size(); i++)
{
cout << Split[i] << endl;
}
return 0;
}
要保留空条目（默认情况下将排除空条目）：
StringSplit ss = mystring;
ss.keep_empty = true;
vector<string> Split = ss.split_string(":DELIM:");
目标是使其类似于C#的Split（）方法，其中拆分字符串非常简单：
String[] Split =
"Hey:cut:what's:cut:your:cut:name?".Split(new[]{":cut:"}, StringSplitOptions.None);
foreach(String X in Split)
{
Console.Write(X);
}
我希望其他人能像我一样觉得这很有用。
我使用以下方法
void split(string in, vector<string>& parts, char separator) {
string::iterator ts, curr;
ts = curr = in.begin();
for(; curr <= in.end(); curr++ ) {
if( (curr == in.end() || *curr == separator) && curr > ts )
parts.push_back( string( ts, curr ));
if( curr == in.end() )
break;
if( *curr == separator ) ts = curr + 1;
}
}
PlasmaHH，我忘记包含删除带有空格的标记的额外检查（curr>ts）。
