在C ++中将字符串转换为向量

Question

Is it possible to easily convert a string to a vector in C++?

string s = "12345"
vector<int>(s.begin(), s.end(), c => c - '0'); // something like that

The goal is to have a vector of ints like { 1, 2, 3, 4, 5 };

I don't want to use loops, I want to write a clear and simple code. (I know that beneath there will be some loop anyway).

The string is always a number.

Answer 1

You could start with

string s = "12345"
vector<int> v(s.begin(), s.end())

and then use <algorithm> 's transform :

transform(
    s.begin(), s.end(), 
    s.begin(), 
    [](char a){return a - '0';});

Answer 2

Maybe not exactly what you want (I don't know how to pull it off in the constructor):

string s = "12345";
vector<int> v;
for_each(s.begin(), s.end(), [&v](char c) {v.push_back(c - '0');});

Answer 3

If your string gets so long that the performance hit from the double iteration matters, you can also do it in just a single pass:

vector<int> v;
v.reserve(str.size());
transform(begin(str), end(str), back_inserter(v),
    [](const auto &c){return c - '0';});

(Or with a C++11 lambda as already shown by others.)

Answer 4

Just two lines of mine :

vector<int> v(s.begin(), s.end());
for(auto& i : v) i = i - '0';

This is simplest one!

Answer 5

One loop with std::transform :

std::vector<int> v(s.size());
std::transform(s.begin(), s.end(), v.begin(), [](char c){return c - '0';});

Answer 6

string s = "1234";
vector<int> v;
for(auto& i : s) v.push_back(i - '0');

One liner!