Text - Character
> (Data|State) Management and Processing > (Data Type|Data Structure) > (Text|String|Character)
Table of Contents
1 - About
A character is an atomic unit of text as specified by ISO/IEC 10646:2000 [ISO/IEC 10646] and is categorized as a primitive data type
A character is the smallest component of written language that has semantic value; refers to the abstract meaning and/or shape …
Characters will not appear as intended unless you have the appropriate font (that contains the appropriate glyph)
Character are the basic unit of organization of encoded text.
A character is usually be represented as an Unicode code point where an int value from 0 to 65535 represents all Unicode code points, including supplementary code points.
2 - Articles Related
3 - Example
A Character can also be simply a set of characters:
- letters,
- numbers,
- symbols (mathematical),
- ideograms,
- logograms (from non-phonetic writing systems such as kanji),
- etc…
For example, the following character set appears in several code pages:
- 26 non-accented letters A through Z ( A,B,C….X,Y,Z)
- 26 non-accented letters a through z ( a,b,c,…x,y,z)
- digits 0 through 9
- special characters: . , : ; ? ( ) ' “ / - _ & + % * = < >
4 - Type/Category
- …
5 - Management
5.1 - Encoding, File Storage
5.2 - Show
Problem: Which character is –
Steps:
- The Character Set is UTF8. We got then hexadecimal in UTF8.
echo $LANG
The Hexadecimal in UTF8 of this character is e2 80 93
. It corresponds to the unicode character 2013 - EN DASH. See Translation of a UTF-8 Multibyte sequence to Unicode - Example 2. 0a
is the end of file.
echo – | hexdump -C
00000000 e2 80 93 0a |....| 00000004
5.3 - Diff
Diff between Characters with an hex tool such as `hexdump` on Unix that output hexadecimal digits
Problem:
- Are this two characters the same ?
– -
Steps:
- The Character Set is UTF8. We got then hexadecimal in UTF8.
echo $LANG
en_US.UTF-8
- The Hexadecimal in UTF8 of the first character is
e2 80 93
. It corresponds to the unicode character 2013 - EN DASH. See Translation of a UTF-8 Multibyte sequence to Unicode - Example 2.0a
is the end of file.
echo – | hexdump -C
00000000 e2 80 93 0a |....| 00000004
- The Hexadecimal in UTF8 of the first character is
2d
. This is the unicode character 2d - Hyphen Minus
echo - | hexdump -C
00000000 2d 0a |-.| 00000002
5.4 - Storage
Each character requires:
- ASCII: one byte of memory
- Unicode - UTF8: 8 bytes
6 - Java
Character.toChars(int)[0]
For example, Character.isLetter(0x2F81A) returns true because the code point value represents a letter (a CJK ideograph).