好的,所以我一直在寻找一种算法,可以帮助我在子字符串中找到一个字符串。 我之前使用的代码来自similar question,但它没有这样做。在字符串C++中查找子字符串(在“hello”中查找“el”)
// might not be exposed publicly, but could be
int index_of(string const& haystack, int haystack_pos, string const& needle) {
// would normally use string const& for all the string parameters in this
// answer, but I've mostly stuck to the prototype you already have
// shorter local name, keep parameter name the same for interface clarity
int& h = haystack_pos;
// preconditions:
assert(0 <= h && h <= haystack.length());
if (needle.empty()) return h;
if (h == haystack.length()) return -1;
if (haystack.compare(h, needle.length(), needle) == 0) {
return h;
}
return index_of(haystack, h+1, needle);
}
int index_of(string haystack, string needle) {
// sets up initial values or the "context" for the common case
return index_of(haystack, 0, needle);
}
这不会返回字符串“hello”上的“el”开始索引,我无法弄清楚。
编辑: OK,让我告诉你更多的包括一些现实生活中的例子代码: 我试图分析一个字符串,它是一个文件我想在我的文件系统来排序的路径。 输入例如是这样的:
输入:/media/seagate/lol/Sons.of.Anarchy.S04.720p.HDTV.x264/Sons.of.Anarchy.S04E01.720p.HDTV.x264-IMMERSE。 mkv
当我尝试通过检测SxxExx的存在来解析此字符串以获取其名称时,我查找“s0”,“S0”等(我知道这不是我刚才尝试的最佳实现看看它是否工作,然后看看代码)。所以,当我使用该输入,我所得到的输出是:
input:/media/seagate/lol/Sons.of.Anarchy.S04.720p.HDTV.x264/Sons.of.Anarchy.S04E01.720p.HDTV.x264-IMMERSE.mkv
aux: 0p.HDTV.x264-IMMERSE.mkv
input:/media/seagate/lol/Sons.of.Anarchy.S04.720p.HDTV.x264/Sons.of.Anarchy.S04E01.720p.HDTV.x264-IMMERSE.mkv
aux: 1.720p.HDTV.x264-IMMERSE.mkv
input:/media/seagate/lol/Sons.of.Anarchy.S04.720p.HDTV.x264/Sons.of.Anarchy.S04E01.720p.HDTV.x264-IMMERSE.mkv
aux: 264-IMMERSE.mkv
预期输出AUX:S04E01.720p.HDTV.x264-IMMERSE.mkv
因此,大家可以看到,它只是看对于字符串中的任何字符和停止,这也占多个有效的“找到”应该只是一个。
在那里我试图用这个是全码:
bool StringWorker::isSeries(size_t &i) {
size_t found1, found2, found3, found4, found5, found6;
found1 = input->find_last_of("S0"); //tried several find functions including the
found2 = input->find_last_of("S1"); //index_of() mentioned above in the post
found3 = input->find_last_of("S2");
found4 = input->find_last_of("s0");
found5 = input->find_last_of("s1");
found6 = input->find_last_of("s2");
if (found1 != string::npos) {
if (input->size() - found1 > 6) {
string aux = input->substr(found1, input->size());
cout << "input:" << *input << endl;
cout << "aux: " << aux << endl;
if (isalpha(aux.at(0)) && isdigit(aux.at(1)) && isdigit(aux.at(2))
&& isalpha(aux.at(3)) && isdigit(aux.at(4))
&& isdigit(aux.at(5))) {
i = found1;
return true;
}
}
}
if (found2 != string::npos) {
if (input->size() - found2 > 6) {
string aux = input->substr(found2, input->size());
cout << "input:" << *input << endl;
cout << "aux: " << aux << endl;
if (isalpha(aux.at(0)) && isdigit(aux.at(1)) && isdigit(aux.at(2))
&& isalpha(aux.at(3)) && isdigit(aux.at(4))
&& isdigit(aux.at(5))) {
i = found2;
return true;
}
}
}
if (found3 != string::npos) {
if (input->size() - found3 > 6) {
string aux = input->substr(found3, input->size());
cout << "input:" << *input << endl;
cout << "aux: " << aux << endl;
if (isalpha(aux.at(0)) && isdigit(aux.at(1)) && isdigit(aux.at(2))
&& isalpha(aux.at(3)) && isdigit(aux.at(4))
&& isdigit(aux.at(5))) {
i = found3;
return true;
}
}
}
if (found4 != string::npos) {
if (input->size() - found4 > 6) {
string aux = input->substr(found4, input->size());
cout << "input:" << *input << endl;
cout << "aux: " << aux << endl;
if (isalpha(aux.at(0)) && isdigit(aux.at(1)) && isdigit(aux.at(2))
&& isalpha(aux.at(3)) && isdigit(aux.at(4))
&& isdigit(aux.at(5))) {
i = found4;
return true;
}
}
}
if (found5 != string::npos) {
if (input->size() - found5 > 6) {
string aux = input->substr(found5, input->size());
cout << "input:" << *input << endl;
cout << "aux: " << aux << endl;
if (isalpha(aux.at(0)) && isdigit(aux.at(1)) && isdigit(aux.at(2))
&& isalpha(aux.at(3)) && isdigit(aux.at(4))
&& isdigit(aux.at(5))) {
i = found5;
return true;
}
}
}
if (found6 != string::npos) {
if (input->size() - found6 > 6) {
string aux = input->substr(found6, input->size());
cout << "input:" << *input << endl;
cout << "aux: " << aux << endl;
if (isalpha(aux.at(0)) && isdigit(aux.at(1)) && isdigit(aux.at(2))
&& isalpha(aux.at(3)) && isdigit(aux.at(4))
&& isdigit(aux.at(5))) {
i = found6;
return true;
}
}
}
return false;
}
你能看到这里有什么问题?
['std :: string :: find'](http://en.cppreference.com/w/cpp/string/basic_string/find)有什么问题? –
'std :: search'有什么问题? –
适合我。您必须错误地使用该功能。发布完整的程序。 – john