std::basic_string_view::remove_prefix

From cppreference.com
constexpr void remove_prefix(size_type n);
(since C++17)

Moves the start of the view forward by n characters.

The behavior is undefined if n > size().

Parameters

n - number of characters to remove from the start of the view

Return value

(none)

Complexity

Constant.

Example

#include <iostream>
#include <algorithm>
#include <string_view>
int main()
{
    std::string str = "   trim me";
    std::string_view v = str;
    v.remove_prefix(std::min(v.find_first_not_of(" "), v.size()));
    std::cout << "String: '" << str << "'\n"
              << "View : '" << v << "'\n";
}

Output:

String: '   trim me'
View : 'trim me'

See also

shrinks the view by moving its end backward
(public member function)