std::transform

 

C++

Linguaggio

Concetti

Libreria di Utilità

Stringhe

Contenitori

Algoritmi

Iteratori

Libreria matematca

Input/output

Localizzazione

Espressioni regolari (C++11)

Operazioni atomicche (C++11)

Multithreading (C++11)

 

Algoritmo libreria

Funzioni Original: Functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
Non modifica le operazioni di sequenza 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
Modifica delle operazioni di sequenza 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
Partizionamento operazioni 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)
Ordinamento delle operazioni (su intervalli ordinati) 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
Binarie (le operazioni di ricerca sui campi ordinati) 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
Impostare le operazioni (su intervalli ordinati) 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
Heap operazioni 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
Minimo / massimo le operazioni 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
Operazioni numeriche 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
Libreria C 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, class UnaryOperation > OutputIt transform( InputIt first1, InputIt last1, OutputIt d_first,                     UnaryOperation unary_op );	(1)
template< class InputIt1, class InputIt2, class OutputIt, class BinaryOperation > OutputIt transform( InputIt1 first1, InputIt1 last1, InputIt2 first2,                     OutputIt d_first, BinaryOperation binary_op );	(2)

std::transform applica la funzione specificata a una vasta e memorizza il risultato in un altro campo, con inizio alle d_first.

Original:

std::transform applies the given function to a range and stores the result in another range, beginning at d_first.

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Nella prima versione unary_op operazione unaria viene applicato alla serie definita da [first1, last1). Nella seconda versione del binary_op operazione binaria viene applicata a coppie di elementi da due intervalli: uno definito dal [first1, last1) e l'altro a inizio first2.

Original:

In the first version unary operation unary_op is applied to the range defined by [first1, last1). In the second version the binary operation binary_op is applied to pairs of elements from two ranges: one defined by [first1, last1) and the other beginning at first2.

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Parametri

first1, last1	-	la prima gamma di elementi per trasformare Original: the first range of elements to transform The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
first2	-	all'inizio del secondo intervallo di elementi da trasformare Original: the beginning of the second range of elements to transform The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
d_first	-	l'inizio del campo di destinazione, può essere uguale o first1 first2 Original: the beginning of the destination range, may be equal to first1 or first2 The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
unary_op	-	unary operation function object that will be applied. The signature of the function should be equivalent to the following:  Ret fun(const Type &a); The signature does not need to have const &. The type  Type must be such that an object of type InputIt can be dereferenced and then implicitly converted to  Type. The type  Ret must be such that an object of type OutputIt can be dereferenced and assigned a value of type  Ret. ​
binary_op	-	binary operation function object that will be applied. The signature of the function should be equivalent to the following:  Ret fun(const Type1 &a, const Type2 &b); The signature does not need to have const &. The types  Type1 and  Type2 must be such that objects of types InputIt1 and InputIt2 can be dereferenced and then implicitly converted to  Type1 and  Type2 respectively. The type  Ret must be such that an object of type OutputIt can be dereferenced and assigned a value of type  Ret. ​
Type requirements
- InputIt must meet the requirements of InputIterator.
- InputIt1 must meet the requirements of InputIterator.
- InputIt2 must meet the requirements of InputIterator.
- OutputIt must meet the requirements of OutputIterator.

Valore di ritorno

iteratore uscita all'elemento passato l'ultimo elemento trasformato.

Original:

output iterator to the element past the last element transformed.

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Complessità

1)

esattamente std::distance(first1, last1) applicazioni di unary_op

Original:

exactly std::distance(first1, last1) applications of unary_op

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2)

esattamente std::distance(first1, last1) applicazioni di binary_op

Original:

exactly std::distance(first1, last1) applications of binary_op

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Requisiti

unary_op binary_op e non hanno effetti collaterali. (C fino + 11)

Original:

unary_op and binary_op have no side effects. (C fino + 11)

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unary_op e binary_op non invalidare le iteratori, inclusi gli iteratori finali, o modificare tutti gli elementi delle catene coinvolte. (dal C++11)

Original:

unary_op and binary_op do not invalidate any iterators, including the end iterators, or modify any elements of the ranges involved. (dal C++11)

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L'intento di questi requisiti è quello di consentire implementazioni parallele o out-of-order di std::transform. Per applicare una funzione a una sequenza in ordine, utilizzare std::for_each.

Original:

The intent of these requirements is to allow parallel or out-of-order implementations of std::transform. To apply a function to a sequence in-order, use std::for_each.

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Possibile implementazione

First version
template<class InputIt, class OutputIt, class UnaryOperation> OutputIt transform(InputIt first1, InputIt last1, OutputIt d_first, UnaryOperation unary_op) { while (first1 != last1) { *d_first++ = unary_op(*first1++); } return d_first; }
Second version
template<class InputIt1, class InputIt2, class OutputIt, class BinaryOperation> OutputIt transform(InputIt first1, InputIt last1, InputIt first2, OutputIt d_first, BinaryOperation binary_op) { while (first1 != last1) { *d_first++ = binary_op(*first1++, *first2++); } return d_first; }

Esempio

Il codice seguente utilizza trasformazione per convertire una stringa in lettere maiuscole utilizzando la funzione toupper:

Original:

The following code uses transform to convert a string to uppercase using the toupper function:

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#include <string>
#include <cctype>
#include <algorithm>
#include <iostream>
 
int main()
{
    std::string s("hello");
    std::transform(s.begin(), s.end(), s.begin(), (int (*)(int))std::toupper);
    std::cout << s;
 }

Output:

HELLO

Vedi anche

for_each	applica una funzione di una serie di elementi Original: applies a function to a range of elements The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (funzione di modello)