std::basic_string::find_first_not_of
性病：基本[医]字符串：查找[医]第一[医]不[医]成
| size_type find_first_not_of( const basic_string& str, size_type pos = 0 ) const; | (1) | |
|---|---|---|
| size_type find_first_not_of( const CharT* s, size_type pos, size_type count ) const; | (2) | |
| size_type find_first_not_of( const CharT* s, size_type pos = 0 ) const; | (3) | |
| size_type find_first_not_of( CharT ch, size_type pos = 0 ) const; | (4) | |
| size_type find_first_not_of( std::basic_string_view<CharT, Traits> sv, size_type pos = 0) const | (5) | (since C++17) |
在给定的字符序列中，查找第一个字符不等于任何一个字符。搜索只考虑间隔。[pos，，，size()29%。如果该字符不在间隔中，npos会被归还。
1%29发现第一个字符不等于str...
2%29发现第一个字符与第一个字符中的任何字符都不相等。count所指向的字符串的字符。s...s可以包含空字符。
3%29查找第一个字符等于字符串中的第一个字符。s字符串的长度由第一个空字符决定。
4%29发现第一个字符不等于ch...
5%29发现第一个字符不等于sv...
在所有情况下，都通过调用Traits::eq...
参数
| str | - | string identifying characters to search for |
|---|---|---|
| pos | - | position for the seach to start from |
| count | - | length of character string identifying characters to search for |
| s | - | pointer to a character string identifying characters to search for |
| ch | - | character identifying characters to search for |
| sv | - | std::basic_string_view identifying the characters to search for |
返回值
已发现字符的位置或npos如果找不到这样的角色。
例外
| 1-4) (none) | (until C++11) |
|---|---|
| 1,4) noexcept specification: noexcept 2,3) (none) | (since C++11)(until C++14) |
| 1) noexcept specification: noexcept 2,3,4) (none) | (since C++14) |
| 5) noexcept specification: noexcept | (since C++17) |
例
二次
#include <string>
#include <iostream>
int main() {
std::string to_search = "Some data with %MACROS to substitute";
std::cout << "Before: " << to_search << '\n';
auto pos = std::string::npos;
while ((pos = to_search.find('%')) != std::string::npos) {
// Permit uppercase letters, lowercase letters and numbers in macro names
const auto after = to_search.find_first_not_of("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", pos + 1
// Now to_search[pos] == '%' and to_search[after] == ' ' (after the 'S')
if(after != std::string::npos)
to_search.replace(pos, after - pos, "some very nice macros"
}
std::cout << "After: " << to_search << '\n';
}
二次
产出：
二次
Before: Some data with %MACROS to substitute
After: Some data with some very nice macros to substitute
二次
另见
| find | find characters in the string (public member function) |
|---|---|
| rfind | find the last occurrence of a substring (public member function) |
| find_first_of | find first occurrence of characters (public member function) |
| find_last_of | find last occurrence of characters (public member function) |
| find_last_not_of | find last absence of characters (public member function) |
© cppreference.com
在CreativeCommonsAttribution下授权-ShareAlike未移植许可v3.0。
http：//en.cppreference.com/w/cpp/string/basic[医]字符串/查找[医]第一[医]不[医]成
