從文件c ++加載原始字符串的更簡潔方法

Question

基本上我想要做的是從一個要編碼為json的文件中加載一個字符串。

我實現這個目標的方式非常簡單，應該是一個簡單的操作：

std::ifstream t(json_path);

std::string stringbuf = std::string(std::istreambuf_iterator<char>(t), std::istreambuf_iterator<char>());

boost::erase_all(stringbuf, "\t");

boost::erase_all(stringbuf, "\n");

boost::erase_all(stringbuf, " ");

有沒有更簡單的方法將文本文件加載到字符串並刪除特殊字符？

Answer 1

您還可以使用std::copy_if和插入迭代器來僅復制您想要的字符，而不是復制所有內容，將字節混合（例如， std::remove_if ），並刪除您不想要的字符。

#include <algorithm>
#include <fstream>
#include <iostream>
#include <iterator>
#include <string>


int
main(int argc, char **argv)
{
    std::string outbuf;
    std::ifstream ins(argv[1]);
    std::copy_if(std::istreambuf_iterator<char>(ins),
                 std::istreambuf_iterator<char>(),
                 std::back_insert_iterator<std::string>(outbuf),
                 [](char c) { return !std::isspace(c); });
    std::cout << outbuf << std::endl;
    return 0;
}

Answer 2

您可以使用std::getline和erase / remove idiom與lambda（或仿函數，如果你沒有C ++ 11支持），像

std::string string_buf(std::istreambuf_iterator<char>(t), {});
string_buf.erase(std::remove_if(string_buf.begin(), string_buf.end(), 
        [](char c) { return std::isspace(c);}), 
        string_buf.end()
);

Answer 3

// Open the file
std::ifstream t(json_path);

// Initialize the string directly, no = sign needed.
// C++11: Let second istreambuf_iterator argument be deduced from the first.
std::string stringbuf(std::istreambuf_iterator<char>(t),  {});

// C++11: Use a lambda to adapt remove_if.
char ws[] = " \t\n";
auto new_end = std::remove_if( stringbuf.begin(), stringbuf.end(),
    []( char c ) { return std::count( ws, ws + 3, c ); } );

// Boost was doing this part for you, but it's easy enough.
stringbuf.erase( new_end, stringbuf.end() );

Answer 4

你可以這樣做：

inFile.open(fileName, ios::in); 

if(inFile.fail()) {
    cout<<"error opening the file.";
} else {
    getline(inFile,paragraph);
    cout << paragraph << endl << endl;
}

numWords=paragraph.length();

while (subscript < numWords) {
    curChar = paragraph.substr(subscript, 1);
    if(curChar==","||curChar=="."||curChar==")"
        ||curChar=="("||curChar==";"||curChar==":"||curChar=="-"
        ||curChar=="\""||curChar=="&"||curChar=="?"||
        curChar=="%"||curChar=="$"||curChar=="!") {
        paragraph.erase(subscript, 1);
        numWords-=1;
    } else {
        subscript+=1;
    }
}

cout<<paragraph<<endl;
inFile.close();