QStringRef 类提供的瘦包裹器围绕 QString 子字符串。 更多...
| 头： | #include <QStringRef> |
| CMake: |
find_package(Qt6 COMPONENTS Core5Compat REQUIRED)
target_link_libraries(mytarget PRIVATE Qt6::Core5Compat) |
| qmake: | QT += core5compat |
注意： 此类的所有函数 可重入 .
| const_iterator | |
| const_reverse_iterator |
| QStringRef (const QStringRef & other ) | |
| QStringRef (const QString * string ) | |
| QStringRef (const QString * string , int position , int length ) | |
| QStringRef () | |
| QStringRef & | operator= (const QStringRef & other ) |
| ~QStringRef () | |
| QStringRef | appendTo (QString * string ) const |
| const QChar | at (int position ) const |
| QChar | back () const |
| QStringRef::const_iterator | begin () const |
| QStringRef::const_iterator | cbegin () const |
| QStringRef::const_iterator | cend () const |
| void | chop (int n ) |
| QStringRef | chopped (int len ) const |
| void | clear () |
| int | compare (const QString & other , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | compare (const QStringRef & other , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | compare (QChar ch , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | compare (QLatin1String other , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | compare (const QByteArray & other , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| QStringRef::const_iterator | constBegin () const |
| const QChar * | constData () const |
| QStringRef::const_iterator | constEnd () const |
| bool | contains (const QString & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | contains (const QStringRef & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | contains (QChar ch , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | contains (QLatin1String str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | contains (QStringView str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | count () const |
| int | count (const QString & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | count (QChar ch , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | count (const QStringRef & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| QStringRef::const_reverse_iterator | crbegin () const |
| QStringRef::const_reverse_iterator | crend () const |
| const QChar * | data () const |
| QStringRef::const_iterator | end () const |
| bool | endsWith (const QString & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | endsWith (QStringView str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | endsWith (QLatin1String str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | endsWith (QChar ch , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | endsWith (const QStringRef & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| QChar | front () const |
| int | indexOf (const QString & str , int from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | indexOf (const QStringRef & str , int from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | indexOf (QStringView str , int from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | indexOf (QChar ch , int from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | indexOf (QLatin1String str , int from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | isEmpty () const |
| bool | isNull () const |
| bool | isRightToLeft () const |
| int | lastIndexOf (const QString & str , int from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | lastIndexOf (const QStringRef & str , int from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | lastIndexOf (QChar ch , int from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | lastIndexOf (QLatin1String str , int from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | lastIndexOf (QStringView str , int from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| QStringRef | left (int n ) const |
| int | length () const |
| int | localeAwareCompare (const QString & other ) const |
| int | localeAwareCompare (const QStringRef & other ) const |
| QStringRef | mid (int position , int n = -1) const |
| int | position () const |
| QStringRef::const_reverse_iterator | rbegin () const |
| QStringRef::const_reverse_iterator | rend () const |
| QStringRef | right (int n ) const |
| int | size () const |
| QList<QStringRef> | split (const QString & sep , Qt::SplitBehavior behavior = Qt::KeepEmptyParts, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| QList<QStringRef> | split (QChar sep , Qt::SplitBehavior behavior = Qt::KeepEmptyParts, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | startsWith (const QString & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | startsWith (QStringView str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | startsWith (QLatin1String str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | startsWith (QChar ch , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | startsWith (const QStringRef & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| const QString * | string () const |
| double | toDouble (bool * ok = nullptr) const |
| float | toFloat (bool * ok = nullptr) const |
| int | toInt (bool * ok = nullptr, int base = 10) const |
| QByteArray | toLatin1 () const |
| QByteArray | toLocal8Bit () const |
| long | toLong (bool * ok = nullptr, int base = 10) const |
| qlonglong | toLongLong (bool * ok = nullptr, int base = 10) const |
| short | toShort (bool * ok = nullptr, int base = 10) const |
| QString | toString () const |
| uint | toUInt (bool * ok = nullptr, int base = 10) const |
| ulong | toULong (bool * ok = nullptr, int base = 10) const |
| qulonglong | toULongLong (bool * ok = nullptr, int base = 10) const |
| ushort | toUShort (bool * ok = nullptr, int base = 10) const |
| QList<uint> | toUcs4 () const |
| QByteArray | toUtf8 () const |
| QStringRef | trimmed () const |
| void | truncate (int position ) |
| const QChar * | unicode () const |
| bool | operator!= (const char * s ) const |
| bool | operator< (const char * s ) const |
| bool | operator<= (const char * s ) const |
| QStringRef & | operator= (const QString * string ) |
| bool | operator== (const char * s ) const |
| bool | operator> (const char * s ) const |
| bool | operator>= (const char * s ) const |
| QChar | operator[] (int position ) const |
| int | compare (const QStringRef & s1 , const QString & s2 , Qt::CaseSensitivity cs = Qt::CaseSensitive) |
| int | compare (const QStringRef & s1 , const QStringRef & s2 , Qt::CaseSensitivity cs = Qt::CaseSensitive) |
| int | compare (const QStringRef & s1 , QLatin1String s2 , Qt::CaseSensitivity cs = Qt::CaseSensitive) |
| int | localeAwareCompare (const QStringRef & s1 , const QString & s2 ) |
| int | localeAwareCompare (const QStringRef & s1 , const QStringRef & s2 ) |
| bool | operator< (const QStringRef & s1 , const QStringRef & s2 ) |
| bool | operator<= (const QStringRef & s1 , const QStringRef & s2 ) |
| bool | operator== (const QStringRef & s1 , const QStringRef & s2 ) |
| bool | operator== (const QString & s1 , const QStringRef & s2 ) |
| bool | operator== (QLatin1String s1 , const QStringRef & s2 ) |
| bool | operator> (const QStringRef & s1 , const QStringRef & s2 ) |
| bool | operator>= (const QStringRef & s1 , const QStringRef & s2 ) |
QStringRef provides a read-only subset of the QString API.
A string reference explicitly references a portion of a string () with a given size (), starting at a specific position ()。调用 toString () returns a copy of the data as a real QString 实例。
This class is designed to improve the performance of substring handling when manipulating substrings obtained from existing QString instances. QStringRef avoids the memory allocation and reference counting overhead of a standard QString by simply referencing a part of the original string. This can prove to be advantageous in low level code, such as that used in a parser, at the expense of potentially more complex code.
For most users, there are no semantic benefits to using QStringRef instead of QString since QStringRef requires attention to be paid to memory management issues, potentially making code more complex to write and maintain.
警告： A QStringRef is only valid as long as the referenced string exists. If the original string is deleted, the string reference points to an invalid memory location.
We suggest that you only use this class in stable code where profiling has clearly identified that performance improvements can be made by replacing standard string operations with the optimized substring handling provided by this class.
另请参阅 隐式共享类 .
[since 5.4]
QStringRef::
const_iterator
该 typedef 在 Qt 5.4 引入。
另请参阅 QStringRef::const_reverse_iterator .
[since 5.7]
QStringRef::
const_reverse_iterator
该 typedef 在 Qt 5.7 引入。
另请参阅 QStringRef::const_iterator .
[default]
QStringRef::
QStringRef
(const
QStringRef
&
other
)
构造副本为 other string reference.
Constructs a string reference to the given string .
Constructs a string reference to the range of characters in the given string specified by the starting position and length in characters.
警告： This function exists to improve performance as much as possible, and performs no bounds checking. For program correctness, position and length must describe a valid substring of string .
This means that the starting position must be positive or 0 and smaller than string 's length, and length must be positive or 0 but smaller than the string's length minus the starting position ; i.e, 0 <= position < string-> length () and 0 <= length <= string-> length () - position must both be satisfied.
Constructs an empty string reference.
[default]
QStringRef
&QStringRef::
operator=
(const
QStringRef
&
other
)
赋值 other string reference to this string reference, and returns the result.
[default]
QStringRef::
~QStringRef
()
Destroys the string reference.
Since this class is only used to refer to string data, and does not take ownership of it, no memory is freed when instances are destroyed.
Appends the string reference to string , and returns a new reference to the combined string data.
返回字符按给定索引 position in the string reference.
position must be a valid index position in the string (i.e., 0 <= position < size ()).
[since 5.10]
QChar
QStringRef::
back
() const
返回字符串中的最后一个字符。如同
at(size() - 1)
.
此函数为兼容 STL (标准模板库) 提供。
警告： 在空字符串调用此函数，将构成未定义行为。
该函数在 Qt 5.10 引入。
另请参阅 front (), at ()，和 operator[] ().
[since 5.4]
QStringRef::const_iterator
QStringRef::
begin
() const
返回常量 STL 样式迭代器 指向字符串中的首个字符。
该函数在 Qt 5.4 引入。
另请参阅 cbegin (), constBegin (), end (), constEnd (), rbegin ()，和 rend ().
[since 5.4]
QStringRef::const_iterator
QStringRef::
cbegin
() const
如同 begin ().
该函数在 Qt 5.4 引入。
另请参阅 begin (), constBegin (), cend (), constEnd (), rbegin ()，和 rend ().
[since 5.4]
QStringRef::const_iterator
QStringRef::
cend
() const
如同 end ().
该函数在 Qt 5.4 引入。
另请参阅 end (), constEnd (), cbegin (), constBegin (), rbegin ()，和 rend ().
[since 5.8]
void
QStringRef::
chop
(
int
n
)
移除 n 个字符从字符串末尾起。
若 n >= size ()，结果为空字符串；若 n 为负，相当于传递 0。
该函数在 Qt 5.8 引入。
另请参阅 QString::chop () 和 truncate ().
[since 5.10]
QStringRef
QStringRef::
chopped
(
int
len
) const
Returns a substring reference to the size () - len leftmost characters of this string.
注意： 行为未定义若 len 为负或大于 size ().
该函数在 Qt 5.10 引入。
另请参阅 endsWith (), left (), right (), mid (), chop ()，和 truncate ().
Clears the contents of the string reference by making it null and empty.
[static]
int
QStringRef::
compare
(const
QStringRef
&
s1
, const
QString
&
s2
,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive)
比较字符串 s1 采用字符串 s2 and returns an integer less than, equal to, or greater than zero if s1 is less than, equal to, or greater than s2 .
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
这是重载函数。
Compares this string with the other string and returns an integer less than, equal to, or greater than zero if this string is less than, equal to, or greater than the other 字符串。
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
相当于
compare(*this, other, cs)
.
这是重载函数。
Compares this string with the other string and returns an integer less than, equal to, or greater than zero if this string is less than, equal to, or greater than the other 字符串。
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
相当于
compare(*this, other, cs)
.
[since 5.14]
int
QStringRef::
compare
(
QChar
ch
,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive) const
这是重载函数。
Compares this string with ch and returns an integer less than, equal to, or greater than zero if this string is less than, equal to, or greater than ch , interpreted as a string of length one.
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
该函数在 Qt 5.14 引入。
这是重载函数。
Compares this string with the other string and returns an integer less than, equal to, or greater than zero if this string is less than, equal to, or greater than the other 字符串。
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
相当于
compare(*this, other, cs)
.
[since 5.8]
int
QStringRef::
compare
(const
QByteArray
&
other
,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive) const
这是重载函数。
Compares this string with other and returns an integer less than, equal to, or greater than zero if this string is less than, equal to, or greater than the other byte array, interpreted as a UTF-8 sequence.
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
相当于
compare(*this, other, cs)
.
该函数在 Qt 5.8 引入。
[static]
int
QStringRef::
compare
(const
QStringRef
&
s1
, const
QStringRef
&
s2
,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive)
这是重载函数。
比较字符串 s1 采用字符串 s2 and returns an integer less than, equal to, or greater than zero if s1 is less than, equal to, or greater than s2 .
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
[static]
int
QStringRef::
compare
(const
QStringRef
&
s1
,
QLatin1String
s2
,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive)
这是重载函数。
比较字符串 s1 采用字符串 s2 and returns an integer less than, equal to, or greater than zero if s1 is less than, equal to, or greater than s2 .
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
[since 5.9]
QStringRef::const_iterator
QStringRef::
constBegin
() const
如同 begin ().
该函数在 Qt 5.9 引入。
另请参阅 begin (), cend (), constEnd (), rbegin ()，和 rend ().
如同 unicode ().
[since 5.9]
QStringRef::const_iterator
QStringRef::
constEnd
() const
如同 end ().
该函数在 Qt 5.9 引入。
另请参阅 end (), cend (), cbegin (), constBegin (), rbegin ()，和 rend ().
返回
true
if this string reference contains an occurrence of the string
str
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
此函数重载 contains()。
返回
true
if this string reference contains an occurrence of the string reference
str
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
此函数重载 contains()。
返回
true
若此字符串包含出现字符
ch
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
此函数重载 contains()。
返回
true
if this string reference contains an occurrence of the string
str
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
[since 5.14]
bool
QStringRef::
contains
(
QStringView
str
,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive) const
此函数重载 contains()。
返回
true
if this string reference contains an occurrence of the string view
str
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 5.14 引入。
Returns the number of characters referred to by the string reference. Equivalent to size () 和 length ().
返回 (潜在重叠) 出现数对于字符串 str in this string reference.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
另请参阅 QString::count (), contains ()，和 indexOf ().
此函数重载 count()。
Returns the number of occurrences of the character ch in the string reference.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
另请参阅 QString::count (), contains ()，和 indexOf ().
此函数重载 count()。
Returns the number of (potentially overlapping) occurrences of the string reference str in this string reference.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
另请参阅 QString::count (), contains ()，和 indexOf ().
[since 5.7]
QStringRef::const_reverse_iterator
QStringRef::
crbegin
() const
如同 rbegin ().
该函数在 Qt 5.7 引入。
另请参阅 begin (), rbegin ()，和 rend ().
[since 5.7]
QStringRef::const_reverse_iterator
QStringRef::
crend
() const
如同 rend ().
该函数在 Qt 5.7 引入。
另请参阅 end (), rend ()，和 rbegin ().
如同 unicode ().
[since 5.4]
QStringRef::const_iterator
QStringRef::
end
() const
返回常量 STL 样式迭代器 pointing to the imaginary character after the last character in the list.
该函数在 Qt 5.4 引入。
另请参阅 cbegin (), constBegin (), end(), constEnd (), rbegin ()，和 rend ().
返回
true
if the string reference ends with
str
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
另请参阅 QString::endsWith () 和 startsWith ().
[since 5.10]
bool
QStringRef::
endsWith
(
QStringView
str
,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive) const
此函数重载 endsWith()。
该函数在 Qt 5.10 引入。
另请参阅 QString::endsWith () 和 startsWith ().
此函数重载 endsWith()。
另请参阅 QString::endsWith () 和 endsWith ().
此函数重载 endsWith()。
返回
true
if the string reference ends with
ch
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
另请参阅 QString::endsWith () 和 endsWith ().
此函数重载 endsWith()。
另请参阅 QString::endsWith () 和 endsWith ().
[since 5.10]
QChar
QStringRef::
front
() const
Returns the first character in the string. Same as
at(0)
.
此函数为兼容 STL (标准模板库) 提供。
警告： 在空字符串调用此函数，将构成未定义行为。
该函数在 Qt 5.10 引入。
另请参阅 back (), at ()，和 operator[] ().
Returns the index position of the first occurrence of the string str in this string reference, searching forward from index position from . Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
若 from is -1, the search starts at the last character; if it is -2, at the next to last character and so on.
另请参阅 QString::indexOf (), lastIndexOf (), contains ()，和 count ().
此函数重载 indexOf()。
Returns the index position of the first occurrence of the string reference str in this string reference, searching forward from index position from . Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
另请参阅 QString::indexOf (), lastIndexOf (), contains ()，和 count ().
[since 5.14]
int
QStringRef::
indexOf
(
QStringView
str
,
int
from
= 0,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive) const
此函数重载 indexOf()。
Returns the index position of the first occurrence of the string view str in this string reference, searching forward from index position from . Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
若 from is -1, the search starts at the last character; if it is -2, at the next to last character and so on.
该函数在 Qt 5.14 引入。
另请参阅 QString::indexOf (), QStringView::indexOf (), lastIndexOf (), contains ()，和 count ().
此函数重载 indexOf()。
Returns the index position of the first occurrence of the character ch in the string reference, searching forward from index position from . Returns -1 if ch could not be found.
另请参阅 QString::indexOf (), lastIndexOf (), contains ()，和 count ().
Returns the index position of the first occurrence of the string str in this string reference, searching forward from index position from . Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
若 from is -1, the search starts at the last character; if it is -2, at the next to last character and so on.
另请参阅 QString::indexOf (), lastIndexOf (), contains ()，和 count ().
返回
true
if the string reference has no characters; otherwise returns
false
.
A string reference is empty if its size is zero.
另请参阅 size ().
返回
true
if this string reference does not reference a string or if the string it references is null (i.e.
QString::isNull
() is true).
另请参阅 size ().
[since 5.9]
bool
QStringRef::
isRightToLeft
() const
返回
true
if the string is read right to left.
该函数在 Qt 5.9 引入。
另请参阅 QString::isRightToLeft ().
Returns the index position of the last occurrence of the string str in this string reference, searching backward from index position from 。若 from is -1 (default), the search starts at the last character; if from is -2, at the next to last character and so on. Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
另请参阅 QString::lastIndexOf (), indexOf (), contains ()，和 count ().
This function overloads lastIndexOf().
Returns the index position of the last occurrence of the string reference str in this string reference, searching backward from index position from 。若 from is -1 (default), the search starts at the last character; if from is -2, at the next to last character and so on. Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
另请参阅 QString::lastIndexOf (), indexOf (), contains ()，和 count ().
This function overloads lastIndexOf().
Returns the index position of the last occurrence of the character ch , searching backward from position from .
另请参阅 QString::lastIndexOf (), indexOf (), contains ()，和 count ().
This function overloads lastIndexOf().
Returns the index position of the last occurrence of the string str in this string reference, searching backward from index position from 。若 from is -1 (default), the search starts at the last character; if from is -2, at the next to last character and so on. Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
另请参阅 QString::lastIndexOf (), indexOf (), contains ()，和 count ().
[since 5.14]
int
QStringRef::
lastIndexOf
(
QStringView
str
,
int
from
= -1,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive) const
This function overloads lastIndexOf().
Returns the index position of the last occurrence of the string view str in this string, searching backward from index position from 。若 from is -1 (default), the search starts at the last character; if from is -2, at the next to last character and so on. Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 5.14 引入。
另请参阅 indexOf (), contains ()，和 count ().
[since 5.2]
QStringRef
QStringRef::
left
(
int
n
) const
Returns a substring reference to the n leftmost characters of the string.
若 n >= size (), or less than zero, a reference to the entire string is returned.
该函数在 Qt 5.2 引入。
另请参阅 right (), mid (), startsWith (), chopped (), chop ()，和 truncate ().
Returns the number of characters referred to by the string reference. Equivalent to size () 和 count ().
[static]
int
QStringRef::
localeAwareCompare
(const
QStringRef
&
s1
, const
QString
&
s2
)
比较 s1 with s2 and returns an integer less than, equal to, or greater than zero if s1 is less than, equal to, or greater than s2 .
The comparison is performed in a locale- and also platform-dependent manner. Use this function to present sorted lists of strings to the user.
另请参阅 compare (), QLocale ，和 Comparing Strings .
这是重载函数。
Compares this string with the other string and returns an integer less than, equal to, or greater than zero if this string is less than, equal to, or greater than the other 字符串。
The comparison is performed in a locale- and also platform-dependent manner. Use this function to present sorted lists of strings to the user.
另请参阅 Comparing Strings .
这是重载函数。
Compares this string with the other string and returns an integer less than, equal to, or greater than zero if this string is less than, equal to, or greater than the other 字符串。
The comparison is performed in a locale- and also platform-dependent manner. Use this function to present sorted lists of strings to the user.
另请参阅 Comparing Strings .
[static]
int
QStringRef::
localeAwareCompare
(const
QStringRef
&
s1
, const
QStringRef
&
s2
)
这是重载函数。
比较 s1 with s2 and returns an integer less than, equal to, or greater than zero if s1 is less than, equal to, or greater than s2 .
The comparison is performed in a locale- and also platform-dependent manner. Use this function to present sorted lists of strings to the user.
另请参阅 Comparing Strings .
[since 5.2]
QStringRef
QStringRef::
mid
(
int
position
,
int
n
= -1) const
Returns a substring reference to n 个字符对于此字符串，起始于指定 position .
若 position exceeds the length of the string, a null reference is returned.
If there are less than n characters available in the string, starting at the given position ，或者若 n is -1 (default), the function returns all characters from the specified position onwards.
该函数在 Qt 5.2 引入。
另请参阅 left (), right (), chopped (), chop ()，和 truncate ().
Returns the starting position in the referenced string that is referred to by the string reference.
[since 5.7]
QStringRef::const_reverse_iterator
QStringRef::
rbegin
() const
返回常量 STL-style reverse iterator pointing to the first character in the string, in reverse order.
该函数在 Qt 5.7 引入。
另请参阅 begin (), crbegin ()，和 rend ().
[since 5.7]
QStringRef::const_reverse_iterator
QStringRef::
rend
() const
返回 STL-style reverse iterator pointing to one past the last character in the string, in reverse order.
该函数在 Qt 5.7 引入。
另请参阅 end (), crend ()，和 rbegin ().
[since 5.2]
QStringRef
QStringRef::
right
(
int
n
) const
Returns a substring reference to the n rightmost characters of the string.
若 n >= size (), or less than zero, a reference to the entire string is returned.
该函数在 Qt 5.2 引入。
另请参阅 left (), mid (), endsWith (), chopped (), chop ()，和 truncate ().
Returns the number of characters referred to by the string reference. Equivalent to length () 和 count ().
[since 5.14]
QList
<
QStringRef
> QStringRef::
split
(const
QString
&
sep
,
Qt::SplitBehavior
behavior
= Qt::KeepEmptyParts,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive) const
Splits the string into substrings references wherever sep occurs, and returns the list of those strings.
见 QString::split () for how sep , behavior and cs interact to form the result.
注意： All references are valid as long this string is alive. Destroying this string will cause all references to be dangling pointers.
该函数在 Qt 5.14 引入。
[since 5.14]
QList
<
QStringRef
> QStringRef::
split
(
QChar
sep
,
Qt::SplitBehavior
behavior
= Qt::KeepEmptyParts,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive) const
这是重载函数。
该函数在 Qt 5.14 引入。
返回
true
if the string reference starts with
str
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
另请参阅 QString::startsWith () 和 endsWith ().
[since 5.10]
bool
QStringRef::
startsWith
(
QStringView
str
,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive) const
This function overloads startsWith().
该函数在 Qt 5.10 引入。
另请参阅 QString::startsWith () 和 endsWith ().
This function overloads startsWith().
另请参阅 QString::startsWith () 和 endsWith ().
This function overloads startsWith().
返回
true
if the string reference starts with
ch
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
另请参阅 QString::startsWith () 和 endsWith ().
This function overloads startsWith().
另请参阅 QString::startsWith () 和 endsWith ().
Returns a pointer to the string referred to by the string reference, or 0 if it does not reference a string.
另请参阅 unicode ().
[since 5.1]
double
QStringRef::
toDouble
(
bool
*
ok
= nullptr) const
Returns the string converted to a
double
值。
Returns an infinity if the conversion overflows or 0.0 if the conversion fails for other reasons (e.g. underflow).
若
ok
不是
nullptr
, failure is reported by setting *
ok
to
false
, and success by setting *
ok
to
true
.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toDouble ()
For historic reasons, this function does not handle thousands group separators. If you need to convert such numbers, use QLocale::toDouble ().
该函数在 Qt 5.1 引入。
另请参阅 QString::toDouble ().
[since 5.1]
float
QStringRef::
toFloat
(
bool
*
ok
= nullptr) const
Returns the string converted to a
float
值。
Returns an infinity if the conversion overflows or 0.0 if the conversion fails for other reasons (e.g. underflow).
若
ok
不是
nullptr
, failure is reported by setting *
ok
to
false
, and success by setting *
ok
to
true
.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toFloat ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toFloat ().
[since 5.1]
int
QStringRef::
toInt
(
bool
*
ok
= nullptr,
int
base
= 10) const
Returns the string converted to an
int
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
若
ok
不是
nullptr
, failure is reported by setting *
ok
to
false
, and success by setting *
ok
to
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toInt ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toInt ().
Returns a Latin-1 representation of the string as a QByteArray .
The returned byte array is undefined if the string contains non-Latin1 characters. Those characters may be suppressed or replaced with a question mark.
另请参阅 toUtf8 (), toLocal8Bit ()，和 QStringEncoder .
Returns the local 8-bit representation of the string as a QByteArray . The returned byte array is undefined if the string contains characters not supported by the local 8-bit encoding.
在 Unix 系统，这相当于 toUtf8 (), on Windows the systems current code page is being used.
If this string contains any characters that cannot be encoded in the locale, the returned byte array is undefined. Those characters may be suppressed or replaced by another.
另请参阅 toLatin1 (), toUtf8 ()，和 QStringEncoder .
[since 5.1]
long
QStringRef::
toLong
(
bool
*
ok
= nullptr,
int
base
= 10) const
Returns the string converted to a
long
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
若
ok
不是
nullptr
, failure is reported by setting *
ok
to
false
, and success by setting *
ok
to
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toLong ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toLong ().
[since 5.1]
qlonglong
QStringRef::
toLongLong
(
bool
*
ok
= nullptr,
int
base
= 10) const
Returns the string converted to a
long long
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
若
ok
不是
nullptr
, failure is reported by setting *
ok
to
false
, and success by setting *
ok
to
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toLongLong ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toLongLong ().
[since 5.1]
short
QStringRef::
toShort
(
bool
*
ok
= nullptr,
int
base
= 10) const
Returns the string converted to a
short
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
若
ok
不是
nullptr
, failure is reported by setting *
ok
to
false
, and success by setting *
ok
to
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toShort ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toShort ().
Returns a copy of the string reference as a QString 对象。
If the string reference is not a complete reference of the string (meaning that position () is 0 and size () 等于 string ()-> size ()), this function will allocate a new string to return.
另请参阅 string ().
[since 5.1]
uint
QStringRef::
toUInt
(
bool
*
ok
= nullptr,
int
base
= 10) const
Returns the string converted to an
无符号 int
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
若
ok
不是
nullptr
, failure is reported by setting *
ok
to
false
, and success by setting *
ok
to
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toUInt ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toUInt ().
[since 5.1]
ulong
QStringRef::
toULong
(
bool
*
ok
= nullptr,
int
base
= 10) const
Returns the string converted to an
unsigned long
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
若
ok
不是
nullptr
, failure is reported by setting *
ok
to
false
, and success by setting *
ok
to
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toULongLong ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toULong ().
[since 5.1]
qulonglong
QStringRef::
toULongLong
(
bool
*
ok
= nullptr,
int
base
= 10) const
Returns the string converted to an
unsigned long long
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
若
ok
不是
nullptr
, failure is reported by setting *
ok
to
false
, and success by setting *
ok
to
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toULongLong ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toULongLong ().
[since 5.1]
ushort
QStringRef::
toUShort
(
bool
*
ok
= nullptr,
int
base
= 10) const
Returns the string converted to an
unsigned short
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
若
ok
不是
nullptr
, failure is reported by setting *
ok
to
false
, and success by setting *
ok
to
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toUShort ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toUShort ().
Returns a UCS-4/UTF-32 representation of the string as a QList <uint>.
UCS-4 is a Unicode codec and therefore it is lossless. All characters from this string will be encoded in UCS-4. Any invalid sequence of code units in this string is replaced by the Unicode's replacement character (
QChar::ReplacementCharacter
, which corresponds to
U+FFFD
).
The returned list is not \0'-terminated.
另请参阅 toUtf8 (), toLatin1 (), toLocal8Bit ()，和 QStringEncoder .
Returns a UTF-8 representation of the string as a QByteArray .
UTF-8 is a Unicode codec and can represent all characters in a Unicode string like QString .
另请参阅 toLatin1 (), toLocal8Bit ()，和 QStringEncoder .
[since 5.1]
QStringRef
QStringRef::
trimmed
() const
返回从开始到结束之间，已移除空白的字符串。
空白意味着任何字符其。
QChar::isSpace
() 返回
true
。这包括 ASCII 字符 \t、\n、\v、\f、\r、及 " "。
不像 QString::simplified ()，trimmed() 只留下内部空白。
该函数在 Qt 5.1 引入。
另请参阅 QString::trimmed ().
[since 5.6]
void
QStringRef::
truncate
(
int
position
)
截取字符串按给定 position 索引。
若指定 position 索引超出字符串末尾，什么都不发生。
若 position 为负，相当于传递 0。
该函数在 Qt 5.6 引入。
另请参阅 QString::truncate ().
Returns a Unicode representation of the string reference. Since the data stems directly from the referenced string, it is not \0'-terminated unless the string reference includes the string's null terminator.
另请参阅 string ().
This function overloads operator!=().
s const char pointer is converted to a QStringRef using the fromUtf8() function.
可以禁用此运算符通过定义
QT_NO_CAST_FROM_ASCII
when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through
QObject::tr
(), for example.
返回
true
if this string is not lexically equal to the parameter string
s
. Otherwise returns
false
.
另请参阅 QT_NO_CAST_FROM_ASCII .
This function overloads operator<().
s const char pointer is converted to a QStringRef using the fromUtf8() function.
可以禁用此运算符通过定义
QT_NO_CAST_FROM_ASCII
when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through
QObject::tr
(), for example.
返回
true
if this string is lexically smaller than the parameter string
s
. Otherwise returns
false
.
另请参阅 QT_NO_CAST_FROM_ASCII .
This function overloads operator<=().
s const char pointer is converted to a QStringRef using the fromUtf8() function.
可以禁用此运算符通过定义
QT_NO_CAST_FROM_ASCII
when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through
QObject::tr
(), for example.
返回
true
if this string is lexically smaller than or equal to the parameter string
s
. Otherwise returns
false
.
另请参阅 QT_NO_CAST_FROM_ASCII .
Constructs a string reference to the given string and assigns it to this string reference, returning the result.
This function overloads operator==().
s byte array is converted to a QStringRef using the fromUtf8() function. This function stops conversion at the first NUL character found, or the end of the byte array.
可以禁用此运算符通过定义
QT_NO_CAST_FROM_ASCII
when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through
QObject::tr
(), for example.
返回
true
if this string is lexically equal to the parameter string
s
. Otherwise returns
false
.
另请参阅 QT_NO_CAST_FROM_ASCII .
This function overloads operator>().
s const char pointer is converted to a QStringRef using the fromUtf8() function.
可以禁用此运算符通过定义
QT_NO_CAST_FROM_ASCII
when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through
QObject::tr
(), for example.
返回
true
if this string is lexically greater than the parameter string
s
. Otherwise returns
false
.
另请参阅 QT_NO_CAST_FROM_ASCII .
此函数重载运算符 >=()。
s const char pointer is converted to a QStringRef using the fromUtf8() function.
可以禁用此运算符通过定义
QT_NO_CAST_FROM_ASCII
when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through
QObject::tr
(), for example.
返回
true
if this string is lexically greater than or equal to the parameter string
s
. Otherwise returns
false
.
另请参阅 QT_NO_CAST_FROM_ASCII .
[since 5.7]
QChar
QStringRef::
operator[]
(
int
position
) const
返回字符按给定索引 position in the string reference.
position must be a valid index position in the string reference (i.e., 0 <= position < size ()).
该函数在 Qt 5.7 引入。
另请参阅 at ().
返回
true
if string reference
s1
is lexically less than string reference
s2
；否则返回
false
.
另请参阅 Comparing Strings .
返回
true
if string reference
s1
is lexically less than or equal to string reference
s2
；否则返回
false
.
另请参阅 Comparing Strings .
返回
true
if string reference
s1
is lexically equal to string reference
s2
；否则返回
false
.
返回
true
若字符串
s1
is lexically equal to string reference
s2
；否则返回
false
.
返回
true
若字符串
s1
is lexically equal to string reference
s2
；否则返回
false
.
返回
true
if string reference
s1
is lexically greater than string reference
s2
；否则返回
false
.
另请参阅 Comparing Strings .
返回
true
if string reference
s1
is lexically greater than or equal to string reference
s2
；否则返回
false
.
另请参阅 Comparing Strings .