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QChar Class Reference
[QtCore module]

The QChar class provides a 16-bit Unicode character. More...

Types

Methods

Static Methods

Special Methods


Detailed Description

This class can be pickled.

The QChar class provides a 16-bit Unicode character.

In Qt, Unicode characters are 16-bit entities without any markup or structure. This class represents such an entity. It is lightweight, so it can be used everywhere. Most compilers treat it like a unsigned short.

QChar provides a full complement of testing/classification functions, converting to and from other formats, converting from composed to decomposed Unicode, and trying to compare and case-convert if you ask it to.

The classification functions include functions like those in the standard C++ header <cctype> (formerly <ctype.h>), but operating on the full range of Unicode characters. They all return true if the character is a certain type of character; otherwise they return false. These classification functions are isNull() (returns true if the character is '\0'), isPrint() (true if the character is any sort of printable character, including whitespace), isPunct() (any sort of punctation), isMark() (Unicode Mark), isLetter() (a letter), isNumber() (any sort of numeric character, not just 0-9), isLetterOrNumber(), and isDigit() (decimal digits). All of these are wrappers around category() which return the Unicode-defined category of each character.

QChar also provides direction(), which indicates the "natural" writing direction of this character. The joining() function indicates how the character joins with its neighbors (needed mostly for Arabic) and finally hasMirrored(), which indicates whether the character needs to be mirrored when it is printed in its "unnatural" writing direction.

Composed Unicode characters (like å) can be converted to decomposed Unicode ("a" followed by "ring above") by using decomposition().

In Unicode, comparison is not necessarily possible and case conversion is very difficult at best. Unicode, covering the "entire" world, also includes most of the world's case and sorting problems. operator==() and friends will do comparison based purely on the numeric Unicode value (code point) of the characters, and toUpper() and toLower() will do case changes when the character has a well-defined uppercase/lowercase equivalent. For locale-dependent comparisons, use QString.localeAwareCompare().

The conversion functions include unicode() (to a scalar), toLatin1() (to scalar, but converts all non-Latin-1 characters to 0), row() (gives the Unicode row), cell() (gives the Unicode cell), digitValue() (gives the integer value of any of the numerous digit characters), and a host of constructors.

QChar provides constructors and cast operators that make it easy to convert to and from traditional 8-bit chars. If you defined QT_NO_CAST_FROM_ASCII and QT_NO_CAST_TO_ASCII, as explained in the QString documentation, you will need to explicitly call fromAscii() or fromLatin1(), or use QLatin1Char, to construct a QChar from an 8-bit char, and you will need to call toAscii() or toLatin1() to get the 8-bit value back.


Type Documentation

QChar.Category

This enum maps the Unicode character categories.

The following characters are normative in Unicode:

Constant Value Description
QChar.Mark_NonSpacing 1 Unicode class name Mn
QChar.Mark_SpacingCombining 2 Unicode class name Mc
QChar.Mark_Enclosing 3 Unicode class name Me
QChar.Number_DecimalDigit 4 Unicode class name Nd
QChar.Number_Letter 5 Unicode class name Nl
QChar.Number_Other 6 Unicode class name No
QChar.Separator_Space 7 Unicode class name Zs
QChar.Separator_Line 8 Unicode class name Zl
QChar.Separator_Paragraph 9 Unicode class name Zp
QChar.Other_Control 10 Unicode class name Cc
QChar.Other_Format 11 Unicode class name Cf
QChar.Other_Surrogate 12 Unicode class name Cs
QChar.Other_PrivateUse 13 Unicode class name Co
QChar.Other_NotAssigned 14 Unicode class name Cn

The following categories are informative in Unicode:

Constant Value Description
QChar.Letter_Uppercase 15 Unicode class name Lu
QChar.Letter_Lowercase 16 Unicode class name Ll
QChar.Letter_Titlecase 17 Unicode class name Lt
QChar.Letter_Modifier 18 Unicode class name Lm
QChar.Letter_Other 19 Unicode class name Lo
QChar.Punctuation_Connector 20 Unicode class name Pc
QChar.Punctuation_Dash 21 Unicode class name Pd
QChar.Punctuation_Open 22 Unicode class name Ps
QChar.Punctuation_Close 23 Unicode class name Pe
QChar.Punctuation_InitialQuote 24 Unicode class name Pi
QChar.Punctuation_FinalQuote 25 Unicode class name Pf
QChar.Punctuation_Other 26 Unicode class name Po
QChar.Symbol_Math 27 Unicode class name Sm
QChar.Symbol_Currency 28 Unicode class name Sc
QChar.Symbol_Modifier 29 Unicode class name Sk
QChar.Symbol_Other 30 Unicode class name So
QChar.NoCategory 0 Qt cannot find an appropriate category for the character.

See also category().

QChar.CombiningClass

QChar.Decomposition

This enum type defines the Unicode decomposition attributes. See the Unicode Standard for a description of the values.

Constant Value
QChar.NoDecomposition 0
QChar.Canonical 1
QChar.Circle 8
QChar.Compat 16
QChar.Final 6
QChar.Font 2
QChar.Fraction 17
QChar.Initial 4
QChar.Isolated 7
QChar.Medial 5
QChar.Narrow 13
QChar.NoBreak 3
QChar.Small 14
QChar.Square 15
QChar.Sub 10
QChar.Super 9
QChar.Vertical 11
QChar.Wide 12

See also decomposition().

QChar.Direction

This enum type defines the Unicode direction attributes. See the Unicode Standard for a description of the values.

In order to conform to C/C++ naming conventions "Dir" is prepended to the codes used in the Unicode Standard.

Constant Value
QChar.DirAL 13
QChar.DirAN 5
QChar.DirB 7
QChar.DirBN 18
QChar.DirCS 6
QChar.DirEN 2
QChar.DirES 3
QChar.DirET 4
QChar.DirL 0
QChar.DirLRE 11
QChar.DirLRO 12
QChar.DirNSM 17
QChar.DirON 10
QChar.DirPDF 16
QChar.DirR 1
QChar.DirRLE 14
QChar.DirRLO 15
QChar.DirS 8
QChar.DirWS 9

See also direction().

QChar.Joining

This enum type defines the Unicode joining attributes. See the Unicode Standard for a description of the values.

Constant Value
QChar.Center 3
QChar.Dual 1
QChar.OtherJoining 0
QChar.Right 2

See also joining().

QChar.SpecialCharacter

Constant Value Description
QChar.Null 0x0000 A QChar with this value isNull().
QChar.Nbsp 0x00a0 Non-breaking space.
QChar.ReplacementCharacter 0xfffd The character shown when a font has no glyph for a certain codepoint. A special question mark character is often used. Codecs use this codepoint when input data cannot be represented in Unicode.
QChar.ObjectReplacementCharacter 0xfffc Used to represent an object such as an image when such objects cannot be presented.
QChar.ByteOrderMark 0xfeff  
QChar.ByteOrderSwapped 0xfffe  
QChar.ParagraphSeparator 0x2029  
QChar.LineSeparator 0x2028  

QChar.UnicodeVersion

Specifies which version of the Unicode standard introduced a certain character.

Constant Value Description
QChar.Unicode_1_1 1 Version 1.1
QChar.Unicode_2_0 2 Version 2.0
QChar.Unicode_2_1_2 3 Version 2.1.2
QChar.Unicode_3_0 4 Version 3.0
QChar.Unicode_3_1 5 Version 3.1
QChar.Unicode_3_2 6 Version 3.2
QChar.Unicode_4_0 7 Version 4.0
QChar.Unicode_4_1 8 Version 4.1
QChar.Unicode_5_0 9 Version 5.0
QChar.Unicode_Unassigned 0 The value is not assigned to any character in version 5.0 of Unicode.

See also unicodeVersion().


Method Documentation

QChar.__init__ (self)

Constructs a null QChar ('\0').

See also isNull().

QChar.__init__ (self, str c)

Constructs a QChar corresponding to ASCII/Latin-1 character ch.

QChar.__init__ (self, QLatin1Char ch)

Constructs a QChar corresponding to ASCII/Latin-1 character ch.

QChar.__init__ (self, bytes c, bytes r)

Constructs a QChar corresponding to ASCII/Latin-1 character ch.

QChar.__init__ (self, int rc)

Constructs a QChar for Unicode cell cell in row row.

See also cell() and row().

QChar.__init__ (self, SpecialCharacter s)

Constructs a QChar for the character with Unicode code point code.

QChar.__init__ (self, QChar)

Constructs a QChar for the character with Unicode code point code.

Category QChar.category (self)

Returns the character's category.

Category QChar.category (int ucs4)

This is an overloaded function.

Returns the category of the UCS-4-encoded character specified by ucs4.

This function was introduced in Qt 4.3.

bytes QChar.cell (self)

Returns the cell (least significant byte) of the Unicode character.

See also row().

bytes QChar.combiningClass (self)

Returns the combining class for the character as defined in the Unicode standard. This is mainly useful as a positioning hint for marks attached to a base character.

The Qt text rendering engine uses this information to correctly position non-spacing marks around a base character.

bytes QChar.combiningClass (int ucs4)

This is an overloaded function.

Returns the combining class for the UCS-4-encoded character specified by ucs4, as defined in the Unicode standard.

UnicodeVersion QChar.currentUnicodeVersion ()

Returns the most recent supported Unicode version.

This function was introduced in Qt 4.8.

QString QChar.decomposition (self)

Decomposes a character into its parts. Returns an empty string if no decomposition exists.

QString QChar.decomposition (int ucs4)

This is an overloaded function.

Decomposes the UCS-4-encoded character specified by ucs4 into its constituent parts. Returns an empty string if no decomposition exists.

Decomposition QChar.decompositionTag (self)

Returns the tag defining the composition of the character. Returns QChar.Single if no decomposition exists.

Decomposition QChar.decompositionTag (int ucs4)

This is an overloaded function.

Returns the tag defining the composition of the UCS-4-encoded character specified by ucs4. Returns QChar.Single if no decomposition exists.

int QChar.digitValue (self)

Returns the numeric value of the digit, or -1 if the character is not a digit.

int QChar.digitValue (int ucs4)

This is an overloaded function.

Returns the numeric value of the digit, specified by the UCS-2-encoded character, ucs2, or -1 if the character is not a digit.

Direction QChar.direction (self)

Returns the character's direction.

Direction QChar.direction (int ucs4)

This is an overloaded function.

Returns the direction of the UCS-4-encoded character specified by ucs4.

QChar QChar.fromAscii (str c)

Converts the ASCII character c to its equivalent QChar. This is mainly useful for non-internationalized software.

An alternative is to use QLatin1Char.

See also fromLatin1(), unicode(), and QTextCodec.codecForCStrings().

QChar QChar.fromLatin1 (str c)

Converts the Latin-1 character c to its equivalent QChar. This is mainly useful for non-internationalized software.

See also fromAscii(), unicode(), and QTextCodec.codecForCStrings().

bool QChar.hasMirrored (self)

Returns true if the character should be reversed if the text direction is reversed; otherwise returns false.

Same as (ch.mirroredChar() != ch).

See also mirroredChar().

int QChar.highSurrogate (int ucs4)

Returns the high surrogate value of a ucs4 code point. The returned result is undefined if ucs4 is smaller than 0x10000.

bool QChar.isDigit (self)

Returns true if the character is a decimal digit (Number_DecimalDigit); otherwise returns false.

bool QChar.isHighSurrogate (self)

Returns true if the QChar is the high part of a utf16 surrogate (ie. if its code point is between 0xd800 and 0xdbff, inclusive).

bool QChar.isHighSurrogate (int ucs4)

Returns true if the UCS-4-encoded character specified by ucs4 is the high part of a utf16 surrogate (ie. if its code point is between 0xd800 and 0xdbff, inclusive).

This function was introduced in Qt 4.7.

bool QChar.isLetter (self)

Returns true if the character is a letter (Letter_* categories); otherwise returns false.

bool QChar.isLetterOrNumber (self)

Returns true if the character is a letter or number (Letter_* or Number_* categories); otherwise returns false.

bool QChar.isLower (self)

Returns true if the character is a lowercase letter, i.e. category() is Letter_Lowercase.

See also isUpper(), toLower(), and toUpper().

bool QChar.isLowSurrogate (self)

Returns true if the QChar is the low part of a utf16 surrogate (ie. if its code point is between 0xdc00 and 0xdfff, inclusive).

bool QChar.isLowSurrogate (int ucs4)

Returns true if the UCS-4-encoded character specified by ucs4 is the low part of a utf16 surrogate (ie. if its code point is between 0xdc00 and 0xdfff, inclusive).

This function was introduced in Qt 4.7.

bool QChar.isMark (self)

Returns true if the character is a mark (Mark_* categories); otherwise returns false.

See QChar.Category for more information regarding marks.

bool QChar.isNull (self)

Returns true if the character is the Unicode character 0x0000 ('\0'); otherwise returns false.

bool QChar.isNumber (self)

Returns true if the character is a number (Number_* categories, not just 0-9); otherwise returns false.

See also isDigit().

bool QChar.isPrint (self)

Returns true if the character is a printable character; otherwise returns false. This is any character not of category Cc or Cn.

Note that this gives no indication of whether the character is available in a particular font.

bool QChar.isPunct (self)

Returns true if the character is a punctuation mark (Punctuation_* categories); otherwise returns false.

bool QChar.isSpace (self)

Returns true if the character is a separator character (Separator_* categories); otherwise returns false.

bool QChar.isSymbol (self)

Returns true if the character is a symbol (Symbol_* categories); otherwise returns false.

bool QChar.isTitleCase (self)

Returns true if the character is a titlecase letter, i.e. category() is Letter_Titlecase.

This function was introduced in Qt 4.3.

See also isLower(), toUpper(), toLower(), and toTitleCase().

bool QChar.isUpper (self)

Returns true if the character is an uppercase letter, i.e. category() is Letter_Uppercase.

See also isLower(), toUpper(), and toLower().

Joining QChar.joining (self)

Returns information about the joining properties of the character (needed for certain languages such as Arabic).

Joining QChar.joining (int ucs4)

This is an overloaded function.

Returns information about the joining properties of the UCS-4-encoded character specified by ucs4 (needed for certain languages such as Arabic).

int QChar.lowSurrogate (int ucs4)

Returns the low surrogate value of a ucs4 code point. The returned result is undefined if ucs4 is smaller than 0x10000.

QChar QChar.mirroredChar (self)

Returns the mirrored character if this character is a mirrored character; otherwise returns the character itself.

See also hasMirrored().

int QChar.mirroredChar (int ucs4)

This is an overloaded function.

Returns the mirrored character if the UCS-4-encoded character specified by ucs4 is a mirrored character; otherwise returns the character itself.

See also hasMirrored().

bool QChar.requiresSurrogates (int ucs4)

Returns true if the UCS-4-encoded character specified by ucs4 can be split into the high and low parts of a utf16 surrogate (ie. if its code point is greater than or equals to 0x10000).

This function was introduced in Qt 4.7.

bytes QChar.row (self)

Returns the row (most significant byte) of the Unicode character.

See also cell().

QChar.setCell (self, bytes acell)

QChar.setRow (self, bytes arow)

int QChar.surrogateToUcs4 (int high, int low)

Converts a UTF16 surrogate pair with the given high and low values to its UCS-4 code point.

int QChar.surrogateToUcs4 (QChar high, QChar low)

Converts a utf16 surrogate pair (high, low) to its ucs4 code point.

str QChar.toAscii (self)

Returns the character value of the QChar obtained using the current codec used to read C strings, or 0 if the character is not representable using this codec. The default codec handles Latin-1 encoded text, but this can be changed to assist developers writing source code using other encodings.

The main purpose of this function is to preserve ASCII characters used in C strings. This is mainly useful for developers of non-internationalized software.

See also toLatin1(), unicode(), and QTextCodec.codecForCStrings().

QChar QChar.toCaseFolded (self)

Returns the case folded equivalent of the character. For most Unicode characters this is the same as toLowerCase().

int QChar.toCaseFolded (int ucs4)

This is an overloaded function.

Returns the case folded equivalent of the UCS-4-encoded character specified by ucs4. For most Unicode characters this is the same as toLowerCase().

str QChar.toLatin1 (self)

Returns the Latin-1 character equivalent to the QChar, or 0. This is mainly useful for non-internationalized software.

See also toAscii(), unicode(), and QTextCodec.codecForCStrings().

QChar QChar.toLower (self)

Returns the lowercase equivalent if the character is uppercase or titlecase; otherwise returns the character itself.

int QChar.toLower (int ucs4)

This is an overloaded function.

Returns the lowercase equivalent of the UCS-4-encoded character specified by ucs4 if the character is uppercase or titlecase; otherwise returns the character itself.

QChar QChar.toTitleCase (self)

Returns the title case equivalent if the character is lowercase or uppercase; otherwise returns the character itself.

int QChar.toTitleCase (int ucs4)

This is an overloaded function.

Returns the title case equivalent of the UCS-4-encoded character specified by ucs4 if the character is lowercase or uppercase; otherwise returns the character itself.

QChar QChar.toUpper (self)

Returns the uppercase equivalent if the character is lowercase or titlecase; otherwise returns the character itself.

int QChar.toUpper (int ucs4)

This is an overloaded function.

Returns the uppercase equivalent of the UCS-4-encoded character specified by ucs4 if the character is lowercase or titlecase; otherwise returns the character itself.

int QChar.unicode (self)

Returns a reference to the numeric Unicode value of the QChar.

UnicodeVersion QChar.unicodeVersion (self)

Returns the Unicode version that introduced this character.

UnicodeVersion QChar.unicodeVersion (int ucs4)

This is an overloaded function.

Returns the Unicode version that introduced the character specified in its UCS-4-encoded form as ucs4.

QString QChar.__add__ (self, QString s2)

bool QChar.__eq__ (self, QChar c2)

bool QChar.__ge__ (self, QChar c2)

bool QChar.__gt__ (self, QChar c2)

int QChar.__hash__ (self)

bool QChar.__le__ (self, QChar c2)

bool QChar.__lt__ (self, QChar c2)

bool QChar.__ne__ (self, QChar c2)

object QChar.__repr__ (self)

object QChar.__str__ (self)


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