std::unique_copy

 

C++

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演算法庫

功能 Original: Functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
修改序列操作 Original: Non-modifying sequence operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
all_of any_of none_of （C++11） （C++11） （C++11） for_each count count_if mismatch equal	find find_if find_if_not （C++11） find_end find_first_of adjacent_find search search_n
修改序列操作 Original: Modifying sequence operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
copy copy_if （C++11） copy_n （C++11） copy_backward move （C++11） move_backward （C++11） fill fill_n transform generate generate_n remove remove_if remove_copy remove_copy_if	replace replace_if replace_copy replace_copy_if swap swap_ranges iter_swap reverse reverse_copy rotate rotate_copy random_shuffle shuffle   （C++11） unique unique_copy
分區操作 Original: Partitioning operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_partitioned （C++11） partition partition_copy （C++11）	stable_partition partition_point （C++11）
排序操作（排序的區間） Original: Sorting operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_sorted （C++11） is_sorted_until （C++11） sort	partial_sort partial_sort_copy stable_sort nth_element
二進制搜索操作（排序的區間） Original: Binary search operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
lower_bound upper_bound	binary_search equal_range
設置操作（排序的區間） Original: Set operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
merge inplace_merge includes	set_difference set_intersection set_symmetric_difference set_union
堆的操作 Original: Heap operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_heap is_heap_until （C++11） make_heap	push_heap pop_heap sort_heap
最小/最大操作 Original: Minimum/maximum operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
max max_element min min_element minmax （C++11） minmax_element （C++11）	lexicographical_compare is_permutation （C++11） next_permutation prev_permutation
數字操作 Original: Numeric operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
iota （C++11） accumulate inner_product	adjacent_difference partial_sum
C庫 Original: C library The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
qsort	bsearch

 

Defined in header <algorithm>
template< class InputIt, class OutputIt > ForwardIt unique_copy( InputIt first, InputIt last,                        OutputIt d_first );	(1)
template< class InputIt, class OutputIt, class BinaryPredicate > ForwardIt unique_copy( InputIt first, InputIt last,                        OutputIt d_first, BinaryPredicate p );	(2)

的元素複製的範圍內[first, last)，在這樣一種方式，有沒有連續相等的元素d_first開始到另一個範圍。只有相等的元素的每個組的第一個元素被複制。的第一個版本使用operator==比較的元素，第二個版本使用給定的二元謂詞p.

Original:

Copies the elements from the range [first, last), to another range beginning at d_first in such a way that there are no consecutive equal elements. Only the first element of each group of equal elements is copied. The first version uses operator== to compare the elements, the second version uses the given binary predicate p.

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參數

first, last	-	元素的範圍內進行處理 Original: the range of elements to process The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
d_first	-	的目標範圍的開頭 Original: the beginning of the destination range The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
p	-	binary predicate which returns ​true if the elements should be treated as equal. The signature of the predicate function should be equivalent to the following: bool pred(const Type1 &a, const Type2 &b); The signature does not need to have const &, but the function must not modify the objects passed to it. The types  Type1 and  Type2 must be such that an object of type ForwardIt can be dereferenced and then implicitly converted to both of them. ​
Type requirements
- InputIt must meet the requirements of InputIterator.
- OutputIt must meet the requirements of OutputIterator.
- The type of dereferenced InputIt must meet the requirements of CopyAssignable.
- The type of dereferenced InputIt must meet the requirements of CopyConstructible. if neither InputIt nor OutputIt satisfies ForwardIterator

返回值

過去的最後寫入的元素的元素的輸出迭代器

Original:

Output iterator to the element past the last written element

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可能的實現

First version
template<class ForwardIt, class OutputIt> ForwardIt unique_copy(ForwardIt first, ForwardIt last, OutputIt d_first) {   if (first == last) return d_first;   *d_first = *first; while (++first != last) { if (!(*d_first == *first)) { *(++d_first) = *first; } } return ++d_first; }
Second version
template<class ForwardIt, class OutputIt, class BinaryPredicate> ForwardIt unique_copy(ForwardIt first, ForwardIt last, OutputIt d_first, BinaryPredicate p) {   if (first == last) return d_first;   *d_first = *first; while (++first != last) { if (!p(*result, *first)) { *(++d_first) = *first; } } return ++d_first; }

為例

下面的程序修剪所有的多個連續的空格在一個常量字元串，並輸出結果

Original:

The following program trims all multiple consecutive spaces in a const string and prints the result

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#include <string>
#include <iostream>
#include <algorithm>
#include <iterator>
 
int main()
{
    std::string s1 = "The      string    with many       spaces!";
    std::cout << "before: " << s1 << '\n';
 
    std::string s2;
    std::unique_copy(s1.begin(), s1.end(), std::back_inserter(s2),
                     [](char c1, char c2){ return c1 == ' ' && c2 == ' '; });
 
    std::cout << "after:  " << s2 << '\n';
}

Output:

before: The      string    with many       spaces!
after:  The string with many spaces!

複雜性

線性first和last之間的距離

Original:

linear in the distance between first and last

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另請參閱

adjacent_find	發現兩個相同的（或一些其他的關係）件彼此相鄰 Original: finds two identical (or some other relationship) items adjacent to each other The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函數模板）
unique	removes consecutive duplicate elements in a range （函數模板）