1. string转map
主要用到 std::getline()
和 std::ws
#include <map>
#include <string>
#include <sstream>
#include <iostream>
std::map<std::string, std::string> mappify1(std::string const& s)
{
std::map<std::string, std::string> m;
std::string key, val;
std::istringstream iss(s);
// iss >> std::ws 将流的前导空格去掉
while(std::getline(std::getline(iss >> std::ws, key, ':') >> std::ws, val))
m[key] = val;
return m;
}
std::map<std::string, std::string> mappify2(std::string const& s)
{
std::map<std::string, std::string> m;
std::string::size_type key_pos = 0;
std::string::size_type key_end;
std::string::size_type val_pos;
std::string::size_type val_end;
while((key_end = s.find(':', key_pos)) != std::string::npos)
{
if((val_pos = s.find_first_not_of(": ", key_end)) == std::string::npos)
break;
val_end = s.find('
', val_pos);
m.emplace(s.substr(key_pos, key_end - key_pos), s.substr(val_pos, val_end - val_pos));
key_pos = val_end;
if(key_pos != std::string::npos)
++key_pos;
}
return m;
}
int main()
{
std::string s = "CA: ABCD
CB: ABFG
CC: AFBV
CD: 4567";
std::cout << "mappify1: " << '
';
auto m = mappify1(s);
for(auto const& p: m)
std::cout << '{' << p.first << " => " << p.second << '}' << '
';
std::cout << "mappify2: " << '
';
m = mappify2(s);
for(auto const& p: m)
std::cout << '{' << p.first << " => " << p.second << '}' << '
';
}
2. trim std::string
简单的rtirm1
std::string s
s.earse(s.find_last_not_of("
") + 1);
比较通用的一个https://stackoverflow.com/a/217605
#include <algorithm>
#include <cctype>
#include <locale>
// trim from start (in place)
static inline void ltrim(std::string &s) {
s.erase(s.begin(), std::find_if(s.begin(), s.end(), [](unsigned char ch) {
return !std::isspace(ch);
}));
}
// trim from end (in place)
static inline void rtrim(std::string &s) {
s.erase(std::find_if(s.rbegin(), s.rend(), [](unsigned char ch) {
return !std::isspace(ch);
}).base(), s.end());
}
// trim from both ends (in place)
static inline void trim(std::string &s) {
ltrim(s);
rtrim(s);
}
// trim from start (copying)
static inline std::string ltrim_copy(std::string s) {
ltrim(s);
return s;
}
// trim from end (copying)
static inline std::string rtrim_copy(std::string s) {
rtrim(s);
return s;
}
// trim from both ends (copying)
static inline std::string trim_copy(std::string s) {
trim(s);
return s;
}
boost提供的
#include <boost/algorithm/string.hpp>
string str1=" hello world! ";
string str2=trim_left_copy(str1); // str2 == "hello world! "
string str3=trim_right_copy(str1); // str3 == " hello world!"
trim(str1); // str1 == "hello world!"
string phone="00423333444";
// remove leading 0 from the phone number
trim_left_if(phone,is_any_of("0")); // phone == "423333444"
std::string str("hello world! ");
boost::trim_right(str);
boost::trim_left(str);
boost::trim(str);