C++ 中字符串的分割

拼搏现实的明天。 2022-06-18 06:11 331阅读 0赞

### C++ 中字符串的分割   ###

2008-05-14 22:18:02| 分类： [ MFC/VC(Visual C+][MFC_VC_Visual C] | 标签：|字号大中小订阅

最近做一个后台是**C++**的项目,要解析**字符串**,很久没有写过**C++**代码了,自己写了一个类来解析,感觉太麻烦,在网上找了一段代码,贴在下面:  
\#include <string>  
\#include <vector>  
\#include <iostream>  
using namespace std;

typedef basic\_string<char>::size\_type S\_T;  
static const S\_T npos = -1;

trim指示是否保留空串，默认为保留。  
vector<string> tokenize(const string& src, string tok, bool trim=false, string null\_subst="")  
\{  
if( src.empty() || tok.empty() ) throw "tokenize: empty string\\0";  
  
vector<string> v;  
S\_T pre\_index = 0, index = 0, len = 0;  
while( (index = src.find\_first\_of(tok, pre\_index)) != npos )  
\{  
if( (len = index-pre\_index)!=0 )  
v.push\_back(src.substr(pre\_index, len));  
else if(trim==false)  
v.push\_back(null\_subst);  
pre\_index = index+1;  
\}  
string endstr = src.substr(pre\_index);  
if( trim==false ) v.push\_back( endstr.empty()? null\_subst:endstr );  
else if( !endstr.empty() ) v.push\_back(endstr);  
return v;  
\}

使用一个完整的串delimit（而不是其中的某个字符）来**分割**src串,没有trim选项，即严格**分割**。  
vector<string> split(const string& src, string delimit, string null\_subst="")  
\{  
if( src.empty() || delimit.empty() ) throw "split: empty string\\0";

vector<string> v;  
S\_T deli\_len = delimit.size();  
long index = npos, last\_search\_position = 0;  
while( (index=src.find(delimit, last\_search\_position))!=npos )  
\{  
if(index==last\_search\_position)  
v.push\_back(null\_subst);  
else  
v.push\_back( src.substr(last\_search\_position, index-last\_search\_position) );  
last\_search\_position = index + deli\_len;  
\}  
string last\_one = src.substr(last\_search\_position);  
v.push\_back( last\_one.empty()? null\_subst:last\_one );  
return v;  
\}

// test  
int main(void)  
\{  
string src = ",ab,cde;,,fg,," ;  
string tok = ",;" ;

vector<string> v1 = tokenize(src, tok ,true);  
vector<string> v2 = tokenize(src, tok ,false, "<null>");

cout<<"-------------v1:"<<endl;  
for(int i=0; i<v1.size();i++)  
\{  
cout<<v1\[i\].c\_str()<<endl;  
\}  
  
cout<<"-------------v2:"<<endl;  
for(int j=0; j<v2.size();j++)  
\{  
cout<<v2\[j\].c\_str()<<endl;  
\}

try\{  
  
string s = "\#\#\#\#\#\#123\#4\#\#\#56\#\#\#\#\#\#\#\#789\#\#\#";  
string del = "";//"\#\#\#";  
vector<string> v3 = split(s, del, "<null>");  
cout<<"-------------v3:"<<endl;  
for(int k=0; k<v3.size();k++)  
\{  
cout<<v3\[k\].c\_str()<<endl;  
\}  
\}  
catch (char \*s) \{  
cout<<s<<endl;  
\}

return 0;  
\}

2、CString版的：

\#include <stdio.h>  
\#include <afx.h>

/\*  
\* 该函数用delimits里的字符拆分s，传出一个CStringList指针pList，  
\* 若trim为真，则不保留**分割**后的空串(注意不是空白字符)。比如：  
\* Tokenize( "a,bc;,d,", ",;", &out\_list, TRUE)  
\* 会返回3个串：a、bc、d。  
\* 若trim为FALSE，则用nullSubst用来替代**分割**后的空串，比如：  
\* Tokenize( "a,bc;,d;", ",;", &out\_list, FALSE,"\[null\]" )  
\* 会返回5个串：a、bc、\[null\]、d、\[null\]。  
\* trim默认为FALSE，nullSubst默认为空串。  
\*/  
void Tokenize(CString s, CString delimits, CStringList\* pList, BOOL trim=FALSE, CString nullSubst="")  
\{  
ASSERT( !s.IsEmpty() && !delimits.IsEmpty() );

s += delimits\[0\];  
for( long index=-1; (index=s.FindOneOf((LPCTSTR)delimits))!=-1; )  
\{  
if(index != 0) pList->AddTail( s.Left(index) );  
else if(!trim) pList->AddTail(nullSubst);  
s = s.Right(s.GetLength()-index-1);  
\}  
\}

/\*  
\* 类似java**字符串**的split()方法。  
\* 使用一个完整的串delimit（而不是其中的某个字符）来**分割**src串,没有trim选项，  
\* 即严格**分割**。num用来确定最多**分割**为多少个串,如果是0（默认），则按照delimit  
\* **分割**，若为1，则返回源串。  
\*/  
void Split(const CString& src, CString delimit, CStringList\* pOutList, int num=0, CString nullSubst="")  
\{  
ASSERT( !src.IsEmpty() && !delimit.IsEmpty() );  
if(num==1)  
\{  
pOutList->AddTail(src);  
return;  
\}

int deliLen = delimit.GetLength();  
long index = -1, lastSearchPosition = 0, cnt = 0;

while( (index=src.Find(delimit, lastSearchPosition))!=-1 )  
\{  
if(index==lastSearchPosition)  
pOutList->AddTail(nullSubst);  
else  
pOutList->AddTail(src.Mid(lastSearchPosition, index-lastSearchPosition));  
lastSearchPosition = index + deliLen;

if(num)  
\{  
\++cnt;  
if(cnt+1==num) break;  
\}  
\}  
CString lastOne = src.Mid(lastSearchPosition);  
pOutList->AddTail( lastOne.IsEmpty()? nullSubst:lastOne);  
\}

// test  
int main(void)  
\{  
CString s = ",ab;cde,f,,;gh,,";  
CString sub = ",;";  
CStringList list1,list2;

Tokenize(s,sub,&list1,TRUE,"no use"); // <-----  
printf("-------\[Tokenize\_trim\]-------\\n");  
POSITION pos1 = list1.GetHeadPosition();  
while( pos1!= NULL )  
\{  
printf( list1.GetNext(pos1) );  
printf("\\n");  
\}  
Tokenize(s,sub,&list2,FALSE,"\[null\]"); // <-----  
printf("------\[Tokenize\_no\_trim\]-----\\n");  
POSITION pos2 = list2.GetHeadPosition();  
while( pos2!= NULL )  
\{  
printf( list2.GetNext(pos2) );  
printf("\\n");  
\}  
  
CStringList list3;  
s = "\#\#\#0123\#\#\#567\#\#\#\#\#\#89\#\#\#1000\#\#\#";  
sub = "\#\#\#";  
Split(s,sub,&list3, 3, "<null>"); // <-----  
printf("------\[Split\]-----\\n");  
POSITION pos3 = list3.GetHeadPosition();  
while( pos3!= NULL )  
\{  
printf( list3.GetNext(pos3) );  
printf("\\n");  
\}  
return 0;  
\}

[MFC_VC_Visual C]: http://sm4llb0y.blog.163.com/blog/#m=0&t=1&c=fks_094064082080088066085074087075093087083064093081