就業培訓     下載中心     Wiki     聯絡
登錄   注冊
  1. 首頁
  2. Qt 6.10.1
  3. Qt Core
  4. C++ 類
  5. iterator

QJsonObject::iterator Class

class QJsonObject ::iterator

The QJsonObject::iterator 類提供 STL 樣式非常量迭代器為 QJsonObject . 更多...

此類 強烈可比較 .

此類 強烈可比較 with QJsonObject::const_iterator .

公共類型

iterator_category

公共函數

iterator ()
QString key () const
(從 6.10 起) QAnyStringView keyView () const
QJsonValueRef value () const
QJsonValueRef operator* () const
QJsonObject::iterator operator+ (qsizetype j ) const
QJsonObject::iterator & operator++ ()
QJsonObject::iterator operator++ (int)
QJsonObject::iterator & operator+= (qsizetype j )
qsizetype operator- (QJsonObject::iterator other ) const
QJsonObject::iterator operator- (qsizetype j ) const
QJsonObject::iterator & operator-- ()
QJsonObject::iterator operator-- (int)
QJsonObject::iterator & operator-= (qsizetype j )
QJsonValueRef * operator-> ()
const QJsonValueConstRef * operator-> () const
QJsonValueRef operator[] (qsizetype j ) const
bool operator!= (const QJsonObject::iterator & lhs , const QJsonObject::const_iterator & rhs )
bool operator!= (const QJsonObject::iterator & lhs , const QJsonObject::iterator & rhs )
bool operator< (const QJsonObject::iterator & lhs , const QJsonObject::const_iterator & rhs )
bool operator< (const QJsonObject::iterator & lhs , const QJsonObject::iterator & rhs )
bool operator<= (const QJsonObject::iterator & lhs , const QJsonObject::const_iterator & rhs )
bool operator<= (const QJsonObject::iterator & lhs , const QJsonObject::iterator & rhs )
bool operator== (const QJsonObject::iterator & lhs , const QJsonObject::const_iterator & rhs )
bool operator== (const QJsonObject::iterator & lhs , const QJsonObject::iterator & rhs )
bool operator> (const QJsonObject::iterator & lhs , const QJsonObject::const_iterator & rhs )
bool operator> (const QJsonObject::iterator & lhs , const QJsonObject::iterator & rhs )
bool operator>= (const QJsonObject::iterator & lhs , const QJsonObject::const_iterator & rhs )
bool operator>= (const QJsonObject::iterator & lhs , const QJsonObject::iterator & rhs )

詳細描述

QJsonObject::iterator allows you to iterate over a QJsonObject and to modify the value (but not the key) stored under a particular key. If you want to iterate over a const QJsonObject , you should use QJsonObject::const_iterator . It is generally good practice to use QJsonObject::const_iterator on a non-const QJsonObject as well, unless you need to change the QJsonObject through the iterator. Const iterators are slightly faster, and improve code readability.

默認 QJsonObject::iterator constructor creates an uninitialized iterator. You must initialize it using a QJsonObject function like QJsonObject::begin (), QJsonObject::end ()，或 QJsonObject::find () before you can start iterating.

Multiple iterators can be used on the same object. Existing iterators will however become dangling once the object gets modified.

另請參閱 QJsonObject::const_iterator , 在 Qt 中支持 JSON ，和 保存和加載遊戲 .

成員類型文檔編製

iterator:: iterator_category

同義詞 std::random_access_iterator_tag indicating this iterator is a random-access iterator.

注意： In Qt versions before 5.6, this was set by mistake to std::bidirectional_iterator_tag .

成員函數文檔編製

iterator:: iterator ()

Constructs an uninitialized iterator.

Functions like key (), value (), and operator++() must not be called on an uninitialized iterator. Use operator=() to assign a value to it before using it.

另請參閱 QJsonObject::begin () 和 QJsonObject::end ().

QString iterator:: key () const

Returns the current item's key.

There is no direct way of changing an item's key through an iterator, although it can be done by calling QJsonObject::erase () followed by QJsonObject::insert ().

另請參閱 value () 和 keyView ().

[since 6.10] QAnyStringView iterator:: keyView () const

Returns the current item's key as a QAnyStringView . This function does not allocate memory.

由於 QJsonObject stores keys in US-ASCII, UTF-8 or UTF-16, the returned QAnyStringView may be in any of these encodings.

There is no direct way of changing an item's key through an iterator, although it can be done by calling QJsonObject::erase () followed by QJsonObject::insert ().

該函數在 Qt 6.10 引入。

另請參閱 key () 和 value ().

QJsonValueRef iterator:: value () const

Returns a modifiable reference to the current item's value.

You can change the value of an item by using value() on the left side of an assignment.

The return value is of type QJsonValueRef , a helper class for QJsonArray and QJsonObject . When you get an object of type QJsonValueRef , you can use it as if it were a reference to a QJsonValue . If you assign to it, the assignment will apply to the element in the QJsonArray or QJsonObject from which you got the reference.

另請參閱 key (), keyView ()，和 operator* ().

QJsonValueRef iterator:: operator* () const

Returns a modifiable reference to the current item's value.

如同 value ().

The return value is of type QJsonValueRef , a helper class for QJsonArray and QJsonObject . When you get an object of type QJsonValueRef , you can use it as if it were a reference to a QJsonValue . If you assign to it, the assignment will apply to the element in the QJsonArray or QJsonObject from which you got the reference.

另請參閱 key () 和 keyView ().

QJsonObject::iterator iterator:: operator+ ( qsizetype j ) const

Returns an iterator to the item at j positions forward from this iterator. If j is negative, the iterator goes backward.

另請參閱 operator- ().

QJsonObject::iterator &iterator:: operator++ ()

前綴 ++ operator, ++i , advances the iterator to the next item in the object and returns an iterator to the new current item.

Calling this function on QJsonObject::end () leads to undefined results.

另請參閱 operator-- ().

QJsonObject::iterator iterator:: operator++ ( int )

The postfix ++ operator, i++ , advances the iterator to the next item in the object and returns an iterator to the previously current item.

這是重載函數。

QJsonObject::iterator &iterator:: operator+= ( qsizetype j )

推進迭代器 j items. If j is negative, the iterator goes backward.

另請參閱 operator-= () 和 operator+ ().

qsizetype iterator:: operator- ( QJsonObject::iterator other ) const

Returns the number of items between the item pointed to by other and the item pointed to by this iterator.

QJsonObject::iterator iterator:: operator- ( qsizetype j ) const

Returns an iterator to the item at j positions backward from this iterator. If j is negative, the iterator goes forward.

另請參閱 operator+ ().

QJsonObject::iterator &iterator:: operator-- ()

前綴 -- operator, --i , makes the preceding item current and returns an iterator pointing to the new current item.

Calling this function on QJsonObject::begin () leads to undefined results.

另請參閱 operator++ ().

QJsonObject::iterator iterator:: operator-- ( int )

The postfix -- operator, i-- , makes the preceding item current and returns an iterator pointing to the previously current item.

這是重載函數。

QJsonObject::iterator &iterator:: operator-= ( qsizetype j )

Makes the iterator go back by j items. If j is negative, the iterator goes forward.

另請參閱 operator+= () 和 operator- ().

QJsonValueRef *iterator:: operator-> ()

Returns a pointer to a modifiable reference to the current item.

const QJsonValueConstRef *iterator:: operator-> () const

Returns a pointer to a constant reference to the current item.

QJsonValueRef iterator:: operator[] ( qsizetype j ) const

Returns a modifiable reference to the item at offset j from the item pointed to by this iterator (the item at position *this + j ).

This function is provided to make QJsonObject iterators behave like C++ pointers.

The return value is of type QJsonValueRef , a helper class for QJsonArray and QJsonObject . When you get an object of type QJsonValueRef , you can use it as if it were a reference to a QJsonValue . If you assign to it, the assignment will apply to the element in the QJsonArray or QJsonObject from which you got the reference.

另請參閱 operator+ ().

相關非成員

[noexcept] bool operator== (const QJsonObject::iterator & lhs , const QJsonObject::const_iterator & rhs )

[noexcept] bool operator== (const QJsonObject::iterator & lhs , const QJsonObject::iterator & rhs )

返迴 true if lhs points to the same item as rhs iterator; otherwise returns false .

另請參閱 operator!= ().

[noexcept] bool operator!= (const QJsonObject::iterator & lhs , const QJsonObject::const_iterator & rhs )

[noexcept] bool operator!= (const QJsonObject::iterator & lhs , const QJsonObject::iterator & rhs )

返迴 true if lhs points to a different item than rhs iterator; otherwise returns false .

另請參閱 operator== ().

[noexcept] bool operator< (const QJsonObject::iterator & lhs , const QJsonObject::const_iterator & rhs )

[noexcept] bool operator< (const QJsonObject::iterator & lhs , const QJsonObject::iterator & rhs )

返迴 true if the item pointed to by lhs iterator is less than the item pointed to by the rhs iterator.

[noexcept] bool operator<= (const QJsonObject::iterator & lhs , const QJsonObject::const_iterator & rhs )

[noexcept] bool operator<= (const QJsonObject::iterator & lhs , const QJsonObject::iterator & rhs )

返迴 true if the item pointed to by lhs iterator is less than or equal to the item pointed to by the rhs iterator.

[noexcept] bool operator> (const QJsonObject::iterator & lhs , const QJsonObject::const_iterator & rhs )

[noexcept] bool operator> (const QJsonObject::iterator & lhs , const QJsonObject::iterator & rhs )

返迴 true if the item pointed to by lhs iterator is greater than the item pointed to by the rhs iterator.

[noexcept] bool operator>= (const QJsonObject::iterator & lhs , const QJsonObject::const_iterator & rhs )

[noexcept] bool operator>= (const QJsonObject::iterator & lhs , const QJsonObject::iterator & rhs )

返迴 true if the item pointed to by lhs iterator is greater than or equal to the item pointed to by the rhs iterator.

內容

  1. 公共類型

  2. 公共函數

  3. 相關非成員

  4. 詳細描述