String segmentation (c + +)

often encountered the problem of string segmentation, summarized here, also convenient for me to use later.

First, using strtok function for string segmentation

Prototype: Char *strtok (char *str, const char *delim);

Features: decomposes a string into a set of strings.

parameter Description:str is the string to be decomposed,Delim is the delimiter string.

return value: a segmented string starting from the beginning of the S tr. NULL is returned when there is no split string .

Other: strtok function thread is unsafe, you can use Strtok_r instead.

Example:

Using Strtok to achieve split
#include <string.h>
#include <stdio.h>


int main ()
{
Char s[] = "Golden Global view,disk * desk";
const char *D = ", *";
Char *p;
p = strtok (s,d);
while (p)
{
printf ("%s\n", p);
P=strtok (NULL,D);
}


return 0;
}

Operating Effect:

second, with STL to split a string

Two functions involving the string class find and substr:
1. Find function
Prototype: size_t find (const string& str, size_t pos = 0) const;
Function: Finds the position where the substring first appears.
Parameter description: STR is a substring and POS is the initial find location.
Return value: If found, returns the first occurrence of the position, otherwise returns String::npos

2. substr function
Prototype: String substr (size_t pos = 0, size_t n = npos) const;
function: Gets substring.
Parameter description: POS is the starting position (default is 0), n is the end position (default is NPOs)
return value: substring

The implementation is as follows:

Full code:

String splitting function
Std::vector<std::string> Split (std::string str,std::string pattern)
{
Std::string::size_type POS;
std::vector<std::string> result;
str+=pattern;//extending strings for ease of operation
int size=str.size ();


for (int i=0; i<size; i++)
{
Pos=str.find (Pattern,i);
if (pos<size)
{
std::string s=str.substr (i,pos-i);
Result.push_back (s);
I=pos+pattern.size ()-1;
}
}
return result;
}

/*
File:split1.cpp
Author:mike
e-mail: [Email protected]
*/
#include <iostream>
#include <string>
#include <vector>


String splitting function
Std::vector<std::string> Split (std::string str,std::string pattern)
{
Std::string::size_type POS;
std::vector<std::string> result;
str+=pattern;//extending strings for ease of operation
int size=str.size ();


for (int i=0; i<size; i++)
{
Pos=str.find (Pattern,i);
if (pos<size)
{
std::string s=str.substr (i,pos-i);
Result.push_back (s);
I=pos+pattern.size ()-1;
}
}
return result;
}


int main ()
{
std::string str;
std::cout<< "Please input str:" <<std::endl;
std::cin>>str;
Getline (STD::CIN,STR);
Std::string pattern;
std::cout<< "Please input pattern:" <<std::endl;
std::cin>>pattern;
Getline (Std::cin,pattern);//used to get a string with spaces
Std::vector<std::string> Result=split (Str,pattern);
std::cout<< "The result:" <<std::endl;
for (int i=0; i<result.size (); i++)
{
std::cout<<result[i]<<std::endl;
}


Std::cin.get ();
Std::cin.get ();
return 0;
}

Operating effect:

Third, using boost for string segmentation

Using the regular expression of the boost library to implement the string segmentation
The implementation is as follows:

Std::vector<std::string> Split (std::string str,std::string s)
{
Boost::regex Reg (S.c_str ());
Std::vector<std::string> VEC;
Boost::sregex_token_iterator It (Str.begin (), Str.end (), reg,-1);
Boost::sregex_token_iterator end;
while (It!=end)
{
Vec.push_back (*it++);
}
return VEC;
}

Full code:

The realization of this program is to use regular expressions to partition the string
Operating environment VC6.0 + Boost Library
/*
File:split2.cpp
Author:mike
e-mail: [Email protected]
*/
#include <iostream>
#include <cassert>
#include <vector>
#include <string>
#include "boost/regex.hpp"


Std::vector<std::string> Split (std::string str,std::string s)
{
Boost::regex Reg (S.c_str ());
Std::vector<std::string> VEC;
Boost::sregex_token_iterator It (Str.begin (), Str.end (), reg,-1);
Boost::sregex_token_iterator end;
while (It!=end)
{
Vec.push_back (*it++);
}
return VEC;
}
int main ()
{
Std::string str,s;
Str= "SSS/DDD/GGG/HH";
s= "/";
Std::vector<std::string> Vec=split (str,s);
for (int i=0,size=vec.size (); i<size;i++)
{
std::cout<<vec[i]<<std::endl;
}
Std::cin.get ();
Std::cin.get ();
return 0;
}

Operating effect:

Add:

Recently found that the boost has its own split function, if you use boost, or directly with Split's good, here is not much to say, the code is as follows:

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

using namespace Std;

int main ()
{
string s = "SSS/DDD,GGG";
Vector<string> Vstr;
Boost::split (Vstr, S, boost::is_any_of (",/"), boost::token_compress_on);
for (Vector<string>::iterator it = Vstr.begin (); It! = Vstr.end (); + + it)
cout << *it << Endl;
return 0;
}

All right, that's it, I hope it helps you.

String segmentation (c + +)