Ася

мой массив слайсится не так как нужно

import pandas as pd

df1 = pd.DataFrame({'col1':['A', 'B', 'C', 'D', 'C'], 'col2': [1,2,3,4,3], 'col3': [5,6,7,8,102]})
df1

df2 = pd.DataFrame({'col1':['C'], 'col2': [3], 'col3': [7]})
df2


df_new = pd.merge(df1, df2, how='outer', indicator=True)
df_new.loc[df_new['_merge'] == 'left_only'].drop('_merge', axis=1)

http://www.trafficengland.com/api/events/getAlerts?start=0&step=100&order=Severity&is_current=1&events=CONGESTION,FULL_CLOSURES,ROADWORKS,INCIDENT,WEATHER,MAJOR_ORGANISED_EVENTS,ABNORMAL_LOADS&unconfirmed=false&completed=false&includeUnconfirmedRoadworks=true&_=1573508267254
http://www.trafficengland.com/api/events/getAlerts?start=100&step=100&order=Severity&is_current=1&events=CONGESTION,FULL_CLOSURES,ROADWORKS,INCIDENT,WEATHER,MAJOR_ORGANISED_EVENTS,ABNORMAL_LOADS&unconfirmed=false&completed=false&includeUnconfirmedRoadworks=true&_=1573508267255

def my_comb(pattern, r):
    comb_list = combinations(pattern, r)
    for c in comb_list:
        yield ''.join(x if x in c else '-' for x in pattern)

>>> list(my_comb('ABC', 2))
['AB-', 'A-C', '-BC']
>>> list(my_comb('ABCDE', 3))
['ABC--', 'AB-D-', 'AB--E', 'A-CD-', 'A-C-E', 'A--DE', '-BCD-', '-BC-E', '-B-DE', '--CDE']

Подскажите как это лучше всего сделать с использованием только стандартных библиотек C++?

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

int main() {

  std::ofstream out_file( "out.txt" );
  std::ifstream in_file( "in.txt" );
  std::string/*stream*/ some_buffer;

  using char_type = decltype(out_file)::char_type;
  using in_iter = std::istream_iterator< char_type >;

  if ( !in_file.is_open() || !out_file.is_open() )
    return EXIT_FAILURE;

  std::transform(in_iter(in_file), in_iter(), std::ostream_iterator< char_type >(out_file),
                 [&some_buffer] (const char_type &c) {

                   if ( !std::isalpha( static_cast<unsigned char>(c) ) || c == '\n' || c == '\r' )
                     return ' ';

                   // if шило, then мыло, буферизуем если надо, и т. п.

                   return c;
                 });

  return EXIT_SUCCESS;
}