C++ å‚考手册
- C++11
- C++14
- C++17
- C++20
- C++ 编译器支æŒæƒ…况表
- 独立与宿主实现
- C++ è¯è¨€
- C++ 关键è¯
- 预处ç†å™¨
- C++ æ ‡å‡†åº“å¤´æ–‡ä»¶
- å…·åè¦æ±‚
- 功能特性测试 (C++20)
- 工具库
- 类型支æŒï¼ˆåŸºæœ¬ç±»åž‹ã€RTTIã€ç±»åž‹ç‰¹æ€§ï¼‰
- 概念库 (C++20)
- 错误处ç†
- 动æ€å†…å˜ç®¡ç†
- 日期和时间工具
- å—符串库
- std::basic_string
- std::basic_string<CharT,Traits,Allocator>::npos
- std::basic_string<CharT,Traits,Allocator>::at
- std::hash (std::string, std::wstring, std::u16string, std::u32string, std::pmr::string, std::pmr::wstring, std::pmr::u16string, std::pmr::u32string)
- std::basic_string<CharT,Traits,Allocator>::assign
- std::basic_string<CharT,Traits,Allocator>::get_allocator
- std::basic_string<CharT,Traits,Allocator>::substr
- std::basic_string<CharT,Traits,Allocator>::basic_string
- std::basic_string<CharT,Traits,Allocator>::operator=
- std::basic_string<CharT,Traits,Allocator>::operator[]
- std::basic_string<CharT,Traits,Allocator>::front
- std::basic_string<CharT,Traits,Allocator>::back
- std::basic_string<CharT,Traits,Allocator>::data
- std::basic_string<CharT,Traits,Allocator>::c_str
- std::basic_string<CharT,Traits,Allocator>::operator basic_string_view
- std::basic_string<CharT,Traits,Allocator>::begin, std::basic_string<CharT,Traits,Allocator>::cbegin
- std::basic_string<CharT,Traits,Allocator>::end, std::basic_string<CharT,Traits,Allocator>::cend
- std::basic_string<CharT,Traits,Allocator>::rbegin, std::basic_string<CharT,Traits,Allocator>::crbegin
- std::basic_string<CharT,Traits,Allocator>::rend, std::basic_string<CharT,Traits,Allocator>::crend
- std::basic_string<CharT,Traits,Allocator>::empty
- std::basic_string<CharT,Traits,Allocator>::size, std::basic_string<CharT,Traits,Allocator>::length
- std::basic_string<CharT,Traits,Allocator>::max_size
- std::basic_string<CharT,Traits,Allocator>::reserve
- std::basic_string<CharT,Traits,Allocator>::capacity
- std::basic_string<CharT,Traits,Allocator>::shrink_to_fit
- std::basic_string<CharT,Traits,Allocator>::clear
- std::basic_string<CharT,Traits,Allocator>::insert
- std::basic_string<CharT,Traits,Allocator>::erase
- std::basic_string<CharT,Traits,Allocator>::push_back
- std::basic_string<CharT,Traits,Allocator>::pop_back
- std::basic_string<CharT,Traits,Allocator>::append
- std::basic_string<CharT,Traits,Allocator>::operator+=
- std::basic_string<CharT,Traits,Allocator>::compare
- std::basic_string<CharT,Traits,Allocator>::starts_with
- std::basic_string<CharT,Traits,Allocator>::ends_with
- std::basic_string<CharT,Traits,Allocator>::replace
- std::basic_string<CharT,Traits,Allocator>::copy
- std::basic_string<CharT,Traits,Allocator>::resize
- std::basic_string<CharT,Traits,Allocator>::swap
- std::basic_string<CharT,Traits,Allocator>::find
- std::basic_string<CharT,Traits,Allocator>::rfind
- std::basic_string<CharT,Traits,Allocator>::find_first_of
- std::basic_string<CharT,Traits,Allocator>::find_first_not_of
- std::basic_string<CharT,Traits,Allocator>::find_last_of
- std::basic_string<CharT,Traits,Allocator>::find_last_not_of
- std::operator+(std::basic_string)
- std::swap(std::basic_string)
- std::literals::string_literals::operator""s
- std::erase, std::erase_if (std::basic_string)
- operator<<,>>(std::basic_string)
- std::getline
- operator==,!=,<,<=,>,>=,<=>(std::basic_string)
- std::stoi, std::stol, std::stoll
- std::stoul, std::stoull
- std::stof, std::stod, std::stold
- std::to_string
- std::to_wstring
- std::basic_string 的推导指引
- std::basic_string_view
- 空终æ¢å—节å—符串
- 空终æ¢å¤šå—节å—符串
- 空终æ¢å®½å—符串
- std::char_traits
- 注释
- 容器库
- è¿ä»£å™¨åº“
- 范围库 (C++20)
- 算法库
- 数值库
- 输入/输出库
- 文件系统库
- 本地化库
- æ£åˆ™è¡¨è¾¾å¼åº“
- 原åæ“作库
- 线程支æŒåº“
- 实验性 C++ 特性
- 有用的资æº
- 索引
- std 符å·ç´¢å¼•
- åç¨‹æ”¯æŒ (C++20)
- C++ 关键è¯
ä½ç½®ï¼šé¦–页 > C++ å‚考手册 >å—符串库 >std::basic_string > std::basic_string<CharT,Traits,Allocator>::find_last_not_of
std::basic_string<CharT,Traits,Allocator>::find_last_not_of
寻找ä¸ç‰äºŽç»™å®šå—符åºåˆ—ä¸ä»»ä½•å—符的最åŽå—符。æœç´¢åªè€ƒè™‘区间 [0, pos] 。若区间ä¸ä¸å˜åœ¨è¿™ç§å—符，则返回 npos 。
1) 寻找ä¸ç‰äºŽ
str ä¸ä»»ä½•å—符的最åŽå—符。2) 寻找ä¸ç‰äºŽèŒƒå›´
[s, s+count) ä¸ä»»ä½•å—符的最åŽå—符。æ¤èŒƒå›´èƒ½åŒ…å«ç©ºå—符。3) 寻找ä¸ç‰äºŽ
s 所指å‘çš„å—符串ä¸ä»»ä½•å—符的最åŽå—符。用 Traits::length(s) 确定å—符串长度。4) 寻找ä¸ç‰äºŽ
ch 的最åŽå—符。5) 如åŒç”¨ std::basic_string_view<CharT, Traits> sv = t; éšå¼è½¬æ¢
t 为 string_view sv ，然åŽå¯»æ‰¾ä¸ç‰äºŽ sv ä¸ä»»ä½•å—符的最åŽå—符。æ¤é‡è½½ä»…è‹¥ std::is_convertible_v<const T&, std::basic_string_view<CharT, Traits>> 为 true 且 std::is_convertible_v<const T&, const CharT*> 为 false æ‰å‚与é‡è½½å†³è®®ã€‚所有情况下å‡è°ƒç”¨ Traits::eq 检查相ç‰æ€§ã€‚
å‚æ•°
| str | - | 鉴别è¦æœç´¢çš„å—符的 string |
| pos | - | æœç´¢ç»“æŸçš„ä½ç½® |
| count | - | 鉴别è¦æœç´¢çš„å—符的å—符串长度 |
| s | - | 指å‘鉴别è¦æœç´¢çš„å—符的å—符串的指针 |
| ch | - | 鉴别è¦æœç´¢çš„å—符的å—符 |
| t | - | 鉴别è¦æœç´¢çš„å—符的对象（å¯è½¬æ¢ä¸º std::basic_string_view ） |
返回值
找到的å—符ä½ç½®ï¼Œæˆ–若找ä¸åˆ°è¿™ç§å—符则为 npos 。
异常
5)
noexcept 规定： Â
noexcept(std::is_nothrow_convertible_v<const T&, std::basic_string_view<charT, traits>>)
缺陷报告
下列更改行为的缺陷报告追溯地应用于以å‰å‡ºç‰ˆçš„ C++ æ ‡å‡†ã€‚
| DR | 应用于 | 出版时的行为 | æ£ç¡®è¡Œä¸º |
|---|---|---|---|
| LWG 2946 | C++17 | string_view é‡è½½åœ¨æŸäº›æƒ…况下导致æ§ä¹‰
|
通过使之为模æ¿æ¥é¿å… |
示例
| æœ¬èŠ‚æœªå®Œæˆ åŽŸå› ï¼šæš‚æ— ç¤ºä¾‹ |