The QLatin1String class provides a thin wrapper around an US-ASCII/Latin-1 encoded string literal. More...
Header: | #include <QLatin1String> |
qmake: | QT += core |
Note: All functions in this class are reentrant.
typedef | const_iterator |
typedef | const_reference |
typedef | difference_type |
typedef | iterator |
typedef | reference |
typedef | size_type |
typedef | value_type |
QLatin1String() | |
QLatin1String(const char *str) | |
QLatin1String(const char *first, const char *last) | |
QLatin1String(const char *str, int size) | |
QLatin1String(const QByteArray &str) | |
QLatin1Char | at(int pos) const |
QLatin1Char | back() const |
QLatin1String::const_iterator | begin() const |
QLatin1String::const_iterator | cbegin() const |
QLatin1String::const_iterator | cend() const |
void | chop(int length) |
QLatin1String | chopped(int length) const |
int | crbegin() const |
int | crend() const |
const char * | data() const |
QLatin1String::const_iterator | end() const |
bool | endsWith(QStringView str, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
bool | endsWith(QLatin1String l1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
bool | endsWith(QChar ch) const |
bool | endsWith(QChar ch, Qt::CaseSensitivity cs) const |
QLatin1Char | front() const |
bool | isEmpty() const |
bool | isNull() const |
const char * | latin1() const |
QLatin1String | left(int length) const |
QLatin1String | mid(int start) const |
QLatin1String | mid(int start, int length) const |
int | rbegin() const |
int | rend() const |
QLatin1String | right(int length) const |
int | size() const |
bool | startsWith(QStringView str, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
bool | startsWith(QLatin1String l1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
bool | startsWith(QChar ch) const |
bool | startsWith(QChar ch, Qt::CaseSensitivity cs) const |
QLatin1String | trimmed() const |
void | truncate(int length) |
bool | operator!=(const QString &other) const |
bool | operator!=(const char *other) const |
bool | operator!=(const QByteArray &other) const |
bool | operator<(const QString &other) const |
bool | operator<(const char *other) const |
bool | operator<(const QByteArray &other) const |
bool | operator<=(const QString &other) const |
bool | operator<=(const char *other) const |
bool | operator<=(const QByteArray &other) const |
bool | operator==(const QString &other) const |
bool | operator==(const char *other) const |
bool | operator==(const QByteArray &other) const |
bool | operator>(const QString &other) const |
bool | operator>(const char *other) const |
bool | operator>(const QByteArray &other) const |
bool | operator>=(const QString &other) const |
bool | operator>=(const char *other) const |
bool | operator>=(const QByteArray &other) const |
QLatin1Char | operator[](int pos) const |
bool | operator!=(QLatin1String s1, QLatin1String s2) |
bool | operator<(QLatin1String s1, QLatin1String s2) |
bool | operator<=(QLatin1String s1, QLatin1String s2) |
bool | operator==(QLatin1String s1, QLatin1String s2) |
bool | operator>(QLatin1String s1, QLatin1String s2) |
bool | operator>=(QLatin1String s1, QLatin1String s2) |
The QLatin1String class provides a thin wrapper around an US-ASCII/Latin-1 encoded string literal.
Many of QString's member functions are overloaded to accept const char *
instead of QString. This includes the copy constructor, the assignment
operator, the comparison operators, and various other functions such as insert(), replace(), and indexOf().
These functions are usually optimized to avoid constructing a QString object for the const char *
data. For example, assuming str
is a QString,
if (str == "auto" || str == "extern" || str == "static" || str == "register") { ... }
is much faster than
if (str == QString("auto") || str == QString("extern") || str == QString("static") || str == QString("register")) { ... }
because it doesn't construct four temporary QString objects and make a deep copy of the character data.
Applications that define QT_NO_CAST_FROM_ASCII
(as explained in the QString documentation) don't have access to QString's const char *
API. To provide an efficient way of specifying constant Latin-1 strings, Qt provides the QLatin1String, which is just a very thin wrapper around a const char *
. Using QLatin1String, the example code above becomes
if (str == QLatin1String("auto") || str == QLatin1String("extern") || str == QLatin1String("static") || str == QLatin1String("register") { ... }
This is a bit longer to type, but it provides exactly the same benefits as the first version of the code, and is faster than converting the Latin-1 strings using QString::fromLatin1().
Thanks to the QString(QLatin1String) constructor, QLatin1String can be used everywhere a QString is expected. For example:
QLabel *label = new QLabel(QLatin1String("MOD"), this);
Note: If the function you're calling with a QLatin1String argument isn't actually overloaded to take QLatin1String, the implicit conversion to QString will trigger a memory allocation, which is usually what you want to avoid by using QLatin1String in the first place. In those cases, using QStringLiteral may be the better option.
See also QString, QLatin1Char, and QStringLiteral.
This typedef provides an STL-style const iterator for QLatin1String.
This typedef was introduced in Qt 5.10.
See also iterator and const_reverse_iterator.
Alias for reference
. Provided for compatibility with the STL.
This typedef was introduced in Qt 5.11.
Alias for int
. Provided for compatibility with the STL.
This typedef was introduced in Qt 5.10.
This typedef provides an STL-style const iterator for QLatin1String.
QLatin1String does not support mutable iterators, so this is the same as const_iterator.
This typedef was introduced in Qt 5.10.
See also const_iterator and reverse_iterator.
Alias for value_type &
. Provided for compatibility with the STL.
This typedef was introduced in Qt 5.10.
Alias for int
. Provided for compatibility with the STL.
This typedef was introduced in Qt 5.10.
Alias for const char
. Provided for compatibility with the STL.
This typedef was introduced in Qt 5.10.
Returns true
if this Latin-1 string ends with string-view str, Latin-1 string l1, or character ch, respectively; otherwise returns false
.
If cs is Qt::CaseSensitive (the default), the search is case-sensitive; otherwise the search is case-insensitive.
This documentation was introduced in Qt 5.10.
See also startsWith().
Returns true
if this Latin-1 string starts with string-view str, Latin-1 string l1, or character ch, respectively; otherwise returns false
.
If cs is Qt::CaseSensitive (the default), the search is case-sensitive; otherwise the search is case-insensitive.
This documentation was introduced in Qt 5.10.
See also endsWith().
Constructs a QLatin1String object that stores a nullptr.
This function was introduced in Qt 5.6.
Constructs a QLatin1String object that stores str.
The string data is not copied. The caller must be able to guarantee that str will not be deleted or modified as long as the QLatin1String object exists.
See also latin1().
Constructs a QLatin1String object that stores first with length (last - first).
The range [first,last)
must remain valid for the lifetime of this Latin-1 string object.
Passing nullptr
as first is safe if last is nullptr
, too, and results in a null Latin-1 string.
The behavior is undefined if last precedes first, first is nullptr
and last is not, or if last - first > INT_MAX
.
This function was introduced in Qt 5.10.
Constructs a QLatin1String object that stores str with size.
The string data is not copied. The caller must be able to guarantee that str will not be deleted or modified as long as the QLatin1String object exists.
See also latin1().
Constructs a QLatin1String object that stores str.
The string data is not copied. The caller must be able to guarantee that str will not be deleted or modified as long as the QLatin1String object exists.
See also latin1().
Returns the character at position pos in this object.
Note: This function performs no error checking. The behavior is undefined when pos < 0 or pos >= size().
This function was introduced in Qt 5.8.
See also operator[]().
Returns the last character in the string. Same as at(size() - 1)
.
This function is provided for STL compatibility.
Warning: Calling this function on an empty string constitutes undefined behavior.
This function was introduced in Qt 5.10.
See also front(), at(), and operator[]().
Returns a const STL-style iterator pointing to the first character in the string.
This function is provided for STL compatibility.
This function was introduced in Qt 5.10.
See also end(), cbegin(), rbegin(), and data().
Same as begin().
This function is provided for STL compatibility.
This function was introduced in Qt 5.10.
See also cend(), begin(), crbegin(), and data().
Same as end().
This function is provided for STL compatibility.
This function was introduced in Qt 5.10.
See also cbegin(), end(), and crend().
Truncates this string by length characters.
Same as *this = left(size() - length)
.
Note: The behavior is undefined when length < 0 or length > size().
This function was introduced in Qt 5.10.
See also mid(), left(), right(), chopped(), and truncate().
Returns the substring of length size() - length starting at the beginning of this object.
Same as left(size() - length)
.
Note: The behavior is undefined when length < 0 or length > size().
This function was introduced in Qt 5.10.
See also mid(), left(), right(), chop(), and truncate().
Same as rbegin().
This function is provided for STL compatibility.
This function was introduced in Qt 5.10.
See also crend(), rbegin(), and cbegin().
Same as rend().
This function is provided for STL compatibility.
This function was introduced in Qt 5.10.
See also crbegin(), rend(), and cend().
Returns the Latin-1 string stored in this object.
Returns a const STL-style iterator pointing to the imaginary character after the last character in the list.
This function is provided for STL compatibility.
This function was introduced in Qt 5.10.
See also begin(), cend(), and rend().
Returns the first character in the string. Same as at(0)
.
This function is provided for STL compatibility.
Warning: Calling this function on an empty string constitutes undefined behavior.
This function was introduced in Qt 5.10.
See also back(), at(), and operator[]().
Returns whether the Latin-1 string stored in this object is empty (size() == 0
) or not.
This function was introduced in Qt 5.10.
Returns whether the Latin-1 string stored in this object is null (data() == nullptr
) or not.
This function was introduced in Qt 5.10.
See also isEmpty() and data().
Returns the Latin-1 string stored in this object.
Returns the substring of length length starting at position 0 in this object.
Note: This function performs no error checking. The behavior is undefined when length < 0 or length > size().
This function was introduced in Qt 5.8.
See also mid(), right(), chopped(), chop(), and truncate().
Returns the substring starting at position start in this object, and extending to the end of the string.
Note: This function performs no error checking. The behavior is undefined when start < 0 or start > size().
This function was introduced in Qt 5.8.
See also left(), right(), chopped(), chop(), and truncate().
This is an overloaded function.
Returns the substring of length length starting at position start in this object.
Note: This function performs no error checking. The behavior is undefined when start < 0, length < 0, or start + length > size().
This function was introduced in Qt 5.8.
See also left(), right(), chopped(), chop(), and truncate().
Returns a const STL-style reverse iterator pointing to the first character in the string, in reverse order.
This function is provided for STL compatibility.
This function was introduced in Qt 5.10.
See also rend(), crbegin(), and begin().
Returns a STL-style reverse iterator pointing to one past the last character in the string, in reverse order.
This function is provided for STL compatibility.
This function was introduced in Qt 5.10.
See also rbegin(), crend(), and end().
Returns the substring of length length starting at position size() - length in this object.
Note: This function performs no error checking. The behavior is undefined when length < 0 or length > size().
This function was introduced in Qt 5.8.
See also mid(), left(), chopped(), chop(), and truncate().
Returns the size of the Latin-1 string stored in this object.
Strips leading and trailing whitespace and returns the result.
Whitespace means any character for which QChar::isSpace() returns true
. This includes the ASCII characters '\t', '\n', '\v', '\f', '\r', and ' '.
This function was introduced in Qt 5.10.
Truncates this string to length length.
Same as *this = left(length)
.
Note: The behavior is undefined when length < 0 or length > size().
This function was introduced in Qt 5.10.
See also mid(), left(), right(), chopped(), and chop().
Returns true
if this string is not equal to string other; otherwise returns false
.
The comparison is based exclusively on the numeric Unicode values of the characters and is very fast, but is not what a human would expect. Consider sorting user-interface strings with QString::localeAwareCompare().
This function overloads operator!=().
The other const char pointer is converted to a QString using the QString::fromUtf8() function.
You can disable this operator by defining 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.
This function was introduced in Qt 4.3.
This function overloads operator!=().
The other byte array is converted to a QString using the QString::fromUtf8() function.
You can disable this operator by defining 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.
This function was introduced in Qt 5.0.
Returns true
if this string is lexically less than the other string; otherwise returns false
.
The comparison is based exclusively on the numeric Unicode values of the characters and is very fast, but is not what a human would expect. Consider sorting user-interface strings using the QString::localeAwareCompare() function.
This is an overloaded function.
The other const char pointer is converted to a QString using the QString::fromUtf8() function.
You can disable this operator by defining 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.
This function was introduced in Qt 4.3.
This is an overloaded function.
The other const char pointer is converted to a QString using the QString::fromUtf8() function.
You can disable this operator by defining 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.
This function was introduced in Qt 5.0.
Returns true
if this string is lexically less than or equal to string other; otherwise returns false
.
The comparison is based exclusively on the numeric Unicode values of the characters and is very fast, but is not what a human would expect. Consider sorting user-interface strings with QString::localeAwareCompare().
This is an overloaded function.
The other const char pointer is converted to a QString using the QString::fromUtf8() function.
You can disable this operator by defining 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.
This function was introduced in Qt 4.3.
This is an overloaded function.
The other array is converted to a QString using the QString::fromUtf8() function.
You can disable this operator by defining 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.
This function was introduced in Qt 5.0.
Returns true
if this string is equal to string other; otherwise returns false
.
The comparison is based exclusively on the numeric Unicode values of the characters and is very fast, but is not what a human would expect. Consider sorting user-interface strings with QString::localeAwareCompare().
This is an overloaded function.
The other const char pointer is converted to a QString using the QString::fromUtf8() function.
You can disable this operator by defining 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.
This function was introduced in Qt 4.3.
This is an overloaded function.
The other byte array is converted to a QString using the QString::fromUtf8() function.
You can disable this operator by defining 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.
This function was introduced in Qt 5.0.
Returns true
if this string is lexically greater than string other; otherwise returns false
.
The comparison is based exclusively on the numeric Unicode values of the characters and is very fast, but is not what a human would expect. Consider sorting user-interface strings with QString::localeAwareCompare().
This is an overloaded function.
The other const char pointer is converted to a QString using the QString::fromUtf8() function.
You can disable this operator by defining 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.
This function was introduced in Qt 4.3.
This is an overloaded function.
The other const char pointer is converted to a QString using the QString::fromUtf8() function.
You can disable this operator by defining 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.
This function was introduced in Qt 5.0.
Returns true
if this string is lexically greater than or equal to string other; otherwise returns false
.
The comparison is based exclusively on the numeric Unicode values of the characters and is very fast, but is not what a human would expect. Consider sorting user-interface strings with QString::localeAwareCompare().
This is an overloaded function.
The other const char pointer is converted to a QString using the QString::fromUtf8() function.
You can disable this operator by defining 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.
This function was introduced in Qt 4.3.
This is an overloaded function.
The other array is converted to a QString using the QString::fromUtf8() function.
You can disable this operator by defining 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.
This function was introduced in Qt 5.0.
Returns the character at position pos in this object.
Note: This function performs no error checking. The behavior is undefined when pos < 0 or pos >= size().
This function was introduced in Qt 5.8.
See also at().
Returns true
if string s1 is lexically unequal to string s2; otherwise returns false
.
Returns true
if string s1 is lexically smaller than string s2; otherwise returns false
.
Returns true
if string s1 is lexically smaller than or equal to string s2; otherwise returns false
.
Returns true
if string s1 is lexically equal to string s2; otherwise returns false
.
Returns true
if string s1 is lexically greater than string s2; otherwise returns false
.
Returns true
if string s1 is lexically greater than or equal to string s2; otherwise returns false
.