为啥我不能在这样的字符串上替换字符?
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【中文标题】为啥我不能在这样的字符串上替换字符?【英文标题】:why can't i replace char on a string like this?为什么我不能在这样的字符串上替换字符? 【发布时间】:2018-05-27 19:16:08 【问题描述】:我正在尝试替换以下映射中的字符:const map<char, vector<char>> ass
,注意我有此字符串 pas
,并且我想将所有(映射值)向量字符替换为对应的映射键,我尝试迭代用这样的for循环映射:(我从***上的另一个问题得到这段代码)
for (auto const &ent1 : ass)
//ent1.first = first key
//ent1.second = second key
所以我尝试像这样迭代地图值向量:
string char1;
string char2;
string wr;
for (auto const &ent1 : ass)
for (int i = 0; i < ent1.second.size(); i++)
specialValues += ent1.second[i];
char2 = ent1.second[i];
char1 = ent1.first;
regex e("([" + char1 + "])");
cout << ("([" + char1 + "])");
cout << char2;
wr = regex_replace("c1a0", e, char2);
所以我希望字符串“c1a0”在循环之后变成“ciao”,但它不会改变任何东西,
我也试过了:
wr = regex_replace("c1a0", e, "o");
输出:c1a0
regex e("([0])");
wr = regex_replace("c1a0", e, char2);
输出:c1a2
我不知道,这对我来说毫无意义。我不明白,你能帮我弄清楚我的代码有什么问题吗?
当然,如果我写的话:
regex e("([0])");
wr = regex_replace("c1a0", e, "o");
它给了我“c1ao”,这就是我想要的。
【问题讨论】:
我认为the "Using loops to replace characters in a string" thread 可以提供帮助。 【参考方案1】:以下代码对我有用:
#include <string>
#include <map>
#include <regex>
#include <iostream>
using namespace std;
int main()
const map<char, vector<char>> ass =
'1', 'i' ,
'0', 'o' ,
;
string char1;
string char2;
string wr = "c1a0";
for (auto const &ent1 : ass)
for (int i = 0; i < ent1.second.size(); i++)
//specialValues += ent1.second[i];
char2 = ent1.second[i];
char1 = ent1.first;
regex e("([" + char1 + "])");
cout << ("([" + char1 + "])") << std::endl;
cout << char2<< std::endl;
wr = regex_replace(wr, e, char2);
cout << wr << std::endl;
但是恕我直言,这里的正则表达式有点矫枉过正。您可以手动迭代字符串并替换字符,如下面的 sn-p:
#include <string>
#include <set>
#include <iostream>
#include <vector>
using namespace std;
struct replace_entry
char with;
std::set<char> what;
;
int main()
const std::vector<replace_entry> replaceTable =
'i', '1' ,
'o', '0' ,
;
string input = "c1a0";
for (auto const &replaceItem : replaceTable)
for (char& c: input )
if(replaceItem.what.end() != replaceItem.what.find(c))
c = replaceItem.with;
cout << input << std::endl;
另一种方法是创建 256 个元素的字符数组
#include <string>
#include <iostream>
class ReplaceTable
private:
char replaceTable_[256];
public:
constexpr ReplaceTable() noexcept
: replaceTable_()
replaceTable_['0'] = 'o';
replaceTable_['1'] = 'i';
constexpr char operator[](char what) const noexcept
return replaceTable_[what];
;
// One time initialization
ReplaceTable g_ReplaceTable;
int main()
std::string input = "c1a0";
// Main loop
for (char& c: input )
if(0 != g_ReplaceTable[c] ) c = g_ReplaceTable[c];
std::cout << input << std::endl;
【讨论】:
好吧,我只是愚蠢地将 char1 与 char2 混淆了,谢谢您的多种解决方案回答 btw以上是关于为啥我不能在这样的字符串上替换字符?的主要内容,如果未能解决你的问题,请参考以下文章