¿Cómo puedo Buscar / Encontrar y Reemplazar en una cadena estándar?
¿Hay alguna manera de reemplazar todas las ocurrencias de una subcadena con otra cadena en std::string
?
Por ejemplo:
void SomeFunction(std::string& str)
{
str = str.replace("hello", "world"); //< I'm looking for something nice like this
}
10 answers
¿Por qué no implementar su propio reemplazo?
void myReplace(std::string& str,
const std::string& oldStr,
const std::string& newStr)
{
std::string::size_type pos = 0u;
while((pos = str.find(oldStr, pos)) != std::string::npos){
str.replace(pos, oldStr.length(), newStr);
pos += newStr.length();
}
}
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2016-06-22 11:47:06
#include <boost/algorithm/string.hpp> // include Boost, a C++ library
...
std::string target("Would you like a foo of chocolate. Two foos of chocolate?");
boost::replace_all(target, "foo", "bar");
Aquí está la documentación oficial sobre replace_all.
Aquí está una presentación que he hecho en 2010 sobre los algoritmos de Cadena de impulso.
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2014-06-05 03:09:19
En C++11, usted puede hacer esto como un one-liner con una llamada a regex_replace
:
#include <string>
#include <regex>
using std::string;
string do_replace( string const & in, string const & from, string const & to )
{
return std::regex_replace( in, std::regex(from), to );
}
string test = "Remove all spaces";
std::cout << do_replace(test, " ", "") << std::endl;
Salida:
Removeallspaces
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2017-02-15 16:38:45
¿Por qué no devolver una cadena modificada?
std::string ReplaceString(std::string subject, const std::string& search,
const std::string& replace) {
size_t pos = 0;
while((pos = subject.find(search, pos)) != std::string::npos) {
subject.replace(pos, search.length(), replace);
pos += replace.length();
}
return subject;
}
Si necesita rendimiento, aquí hay una función optimizada que modifica la cadena de entrada, no crea una copia de la cadena:
void ReplaceStringInPlace(std::string& subject, const std::string& search,
const std::string& replace) {
size_t pos = 0;
while((pos = subject.find(search, pos)) != std::string::npos) {
subject.replace(pos, search.length(), replace);
pos += replace.length();
}
}
Pruebas:
std::string input = "abc abc def";
std::cout << "Input string: " << input << std::endl;
std::cout << "ReplaceString() return value: "
<< ReplaceString(input, "bc", "!!") << std::endl;
std::cout << "ReplaceString() input string not changed: "
<< input << std::endl;
ReplaceStringInPlace(input, "bc", "??");
std::cout << "ReplaceStringInPlace() input string modified: "
<< input << std::endl;
Salida:
Input string: abc abc def
ReplaceString() return value: a!! a!! def
ReplaceString() input string not modified: abc abc def
ReplaceStringInPlace() input string modified: a?? a?? def
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2013-02-04 00:32:45
Mi búsqueda y reemplazo in situ en línea templatizada:
template<class T>
int inline findAndReplace(T& source, const T& find, const T& replace)
{
int num=0;
typename T::size_t fLen = find.size();
typename T::size_t rLen = replace.size();
for (T::size_t pos=0; (pos=source.find(find, pos))!=T::npos; pos+=rLen)
{
num++;
source.replace(pos, fLen, replace);
}
return num;
}
Devuelve un recuento del número de elementos sustituidos (para usar si desea ejecutar esto sucesivamente, etc.). Para usarlo:
std::string str = "one two three";
int n = findAndReplace(str, "one", "1");
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2013-10-30 20:19:02
La forma más fácil (ofreciendo algo cercano a lo que escribiste) es usar Boost.Regex, específicamente regex_replace.
Std::string ha incorporado los métodos find() y replace (), pero son más engorrosos de trabajar ya que requieren lidiar con índices y longitudes de cadena.
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2009-09-29 19:18:50
Creo que esto funcionaría. Toma const char * ' s como parámetro.
//params find and replace cannot be NULL
void FindAndReplace( std::string& source, const char* find, const char* replace )
{
//ASSERT(find != NULL);
//ASSERT(replace != NULL);
size_t findLen = strlen(find);
size_t replaceLen = strlen(replace);
size_t pos = 0;
//search for the next occurrence of find within source
while ((pos = source.find(find, pos)) != std::string::npos)
{
//replace the found string with the replacement
source.replace( pos, findLen, replace );
//the next line keeps you from searching your replace string,
//so your could replace "hello" with "hello world"
//and not have it blow chunks.
pos += replaceLen;
}
}
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2013-04-22 03:02:20
#include <iostream>
#include <string>
#include <boost/algorithm/string.hpp>
#include <boost/tokenizer.hpp>
#include <boost/foreach.hpp>
using namespace boost::algorithm;
using namespace std;
using namespace boost;
void highlighter(string terms, string text) {
char_separator<char> sep(" ");
tokenizer<char_separator<char> > tokens(terms, sep);
BOOST_FOREACH(string term, tokens) {
boost::replace_all(text, term, "<b>" + term + "</b>");
}
cout << text << endl;
}
int main(int argc, char **argv)
{
cout << "Search term highlighter" << endl;
string text("I love boost library, and this is a test of boost library!");
highlighter("love boost", text);
}
Me encanta boost library, y esta es una prueba de boost library!
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2016-07-15 20:35:53
// Replace all occurrences of searchStr in str with replacer
// Each match is replaced only once to prevent an infinite loop
// The algorithm iterates once over the input and only concatenates
// to the output, so it should be reasonably efficient
std::string replace(const std::string& str, const std::string& searchStr,
const std::string& replacer)
{
// Prevent an infinite loop if the input is empty
if (searchStr == "") {
return str;
}
std::string result = "";
size_t pos = 0;
size_t pos2 = str.find(searchStr, pos);
while (pos2 != std::string::npos) {
result += str.substr(pos, pos2-pos) + replacer;
pos = pos2 + searchStr.length();
pos2 = str.find(searchStr, pos);
}
result += str.substr(pos, str.length()-pos);
return result;
}
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2017-09-21 08:01:44
#include <string>
using std::string;
void myReplace(string& str,
const string& oldStr,
const string& newStr) {
if (oldStr.empty()) {
return;
}
for (size_t pos = 0; (pos = str.find(oldStr, pos)) != string::npos;) {
str.replace(pos, oldStr.length(), newStr);
pos += newStr.length();
}
}
La comprobación de que oldStr está vacía es importante. Si por alguna razón ese parámetro está vacío te quedarás atascado en un bucle infinito.
Pero sí use la solución probada de C++11 o Boost si puede.
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2017-12-13 14:33:39