I'm looking for a symbol which meaning is "things that should not be in Unicode".
Does such Unicode character exist (yet)? If yes, what's the codepoint? If not, how do I propose for it?
The REPLACEMENT CHARACTER (U+FFFD) � should be used for characters that can't be represented. From the link:
used to replace an incoming character whose value is unknown or unrepresentable in Unicode
Related
As far as I understand, a character encoding maps bits to integers and a character set maps integers to characters.
So in the Unicode character set there is a telephone character. It is represented using the integer 9742, more commonly represented using Hexadecimal as 260E. This is then saved to a file using UTF-8 which translates the integer 9742 into 10011000001110. Please correct me if I am wrong.
Yesterday I created a text file that used the Unicode character set and UTF-8 encoding and I saved it to my desktop. I then reopened the file in my text editor and started to manually switch the character sets for fun. Unsurprisingly there were problems and odd characters starting displaying! I noticed that only some of the characters are misrepresented though. This got me thinking, why do only some of the characters break? Why not all?
Someone told me that the characters breaking are those outside the original ASCII specification. Upon reflection this seemed to make sense, as it's only non US characters that break. I was told that because all character sets use the ASCII character set up to the first 128 characters they will remain unbroken, and that it's the characters above 127 that break. Please correct me if I am wrong.
Finally, I got thinking. Are there any character sets that don't respect ASCII? If so, what are they called and what are they used for?
Based on my findings from the comments I am able to answer my own question. Thank you to everyone who commented!
Yes, there are a couple; EBCDIC and Baudot.
I've read that we must use Unicode values inside the content CSS property i.e. \ followed by the special character's hexadecimal number.
But what characters, other than alphanumerics, are actually allowed to be placed as is in the value of content property? (Google has no clue, hence the question.)
The rules for “escaping” characters are in the CSS 2.1 specification, clause 4.1.3 Characters and case. The special rules for quoted strings, as in content property value, are in clause 4.3.7 Strings. Within a quoted string, any character may appear as such, except for the character used to quote the string (" or '), a newline character, or a backslash character \.
The information that you must use \ escapes is thus wrong. You may use them, and may even need to use them if the character encoding of the document containing the style sheet does not let you enter all characters directly. But if the encoding is UTF-8, and is properly declared, then you can write content: '☺ Я Ω ⁴ ®'.
As far as I know, you can insert any Unicode character. (Here's a useful list of Unicode characters and their codes.)
To utilize these codes, you must escape them, like so:
U+27BA Becomes \27BA
Or, alternatively, I think you may just be able to escape the character itself:
content: '\➺';
Source: http://mathiasbynens.be/notes/css-escapes
I am working on decoding text. I am trying to find the character code for the — character, not to be mistaken for -, in ASCII. I have tried unsuccessfully. Does anybody know how to convert it?
Quotation from wiki (Em dash)
When an actual em dash is unavailable—as in the ASCII character set—a double ("--") or triple hyphen-minus ("---") is used. In Unicode, the em dash is U+2014 (decimal 8212).
Em dash character is not a part of ASCII character set.
— is known as an Em Dash. It's character code is \u2014. It is not an ASCII character, so you cannot decode it with the ASCII character set because it is not in the ASCII character table. You would probably want to use UTF8 instead.
Windows
For Windows on a keyboard with a Numeric keypad:
Use Alt+0150 (en dash), Alt+0151 (em dash), or Alt+8722 (minus sign) using the numeric keypad.
This character does not exist in ASCII, but only in Unicode, usually encoded by UTF-8.
In UTF-8, characters are encoded by 2- or 3-byte sequences (or occasionally longer), where none of the two or three bytes is a valid ASCII code, where all of them are outside the ASCII range of 0 through 127.
One suspects that the foregoing only partly answers your question, but if so then this is probably because your question is, inadvertently, only partly asked. For further details, you can extend your question with more specifics.
The character — is not part of the ASCII set.
But if you are looking to convert it to some other format (like U+hex), you can use this online tool. Put your character into the first green box and click "Convert" (above the box)
further below you'll find a number of different codes, including U+hex:
U+2014
Feel free to edit this answer if the link breaks or leave a comment so I can find a replacement.
Alt + 0151 seems to do the trick—perhaps it doesn't work on all keyboards.
alt-196 - while holding down the 'Alt' key, type 196 on the numeric keypad, then release the 'Alt' key
I'm looking at the IsCharAlphaNumeric Windows API function. As it only takes a single TCHAR, it obviously can't make any decisions about surrogate pairs for UTF16 content. Does that mean that there are no alphanumeric characters that are surrogate pairs?
Characters outside the BMP can be letters. (Michael Kaplan recently discussed a bug in the classification of the character U+1F48C.) But IsCharAlphaNumeric cannot see characters outside the BMP (for the reasons you noted), so you cannot obtain classification information for them that way.
If you have a surrogate pair, call GetStringType with cchSrc = 2 and check for C1_ALPHA and C1_DIGIT.
Edit: The second half of this answer is incorrect GetStringType does not support surrogate pairs.
You can determine yourself by looking at the Unicode plane assignment what you are missing by not being able to inspect non-BMP codepoints.
For example, you won't be able to identify imperial Aramaic characters as alphanumeric. Shame.
Does that mean that there are no alphanumeric characters that are surrogate pairs?
No, there are supplementary code-points that are in the letter group.
Comparing a char to a code-point?
For example, Character.isLetter('\uD840') returns false, even though this specific value if followed by any low-surrogate value in a string would represent a letter.
Where can I get a list of ASCII codes corresponding to Japanese kanji, hiragana and katakana characters. I am doing a java function and Javascript which determines wether it is a Japanese character. What is its range in the ASCII code?
ASCII stands for American Standard Code for Information Interchange, only includes 128 characters (not all of them even printable), and is based on the needs of American use circa 1960. It includes nothing related to any Japanese characters.
I believe you want the Unicode code points for some characters, which you can lookup in the charts provided by unicode.org.
Please see my similar question regarding Kanji/Kana characters. As #coobird mentions it may be tricky to decide what range you want to check against since many Kanji overlap with Chinese characters.
In short, the Unicode ranges for hiragana and katakana are:
Hiragana: Unicode: 3040-309F
Katakana: Unicode: 30A0–30FF
If you find this answer useful please upvote #coobird's answer to my question as well.
がんばって！
Well it has been a while, but here's a link to tables of hiragana, katakana, kanji etc and their Unicodes...
http://www.rikai.com/library/kanjitables/kanji_codes.unicode.shtml
BUT, as you probably know Unicodes are hexadecimal. You can translate them into decimal numbers using Windows Calc in programmer mode and then input that number as an ASCII code and it will produce the character you want, well depending on what you're putting it into. It will in MS Wordpad and Word(not Notepad).
For example the hiragana ぁ is 3041 in Unicode. 3041 is hexadecimal and translates to 12353 in decimal. If you enter 12353 as an ASCII code into Wordpad or Word i.e hold Alt, enter 12353 on the number-pad then release Alt, it will print ぁ. The range of Japanese characters seems to be Hiragana:3040 - 309f(12352-12447 in ASCII), Katakana:30a0 - 30ff(12448-12543 in ASCII), Kanji: 4e00-4DB5(19968-19893 ASCII), so there are several ranges. There's also a half-width katakana range on that chart.
Japanese characters won't be in the ASCII range, they'll be in Unicode. What do you want, just the char value for each character?
I won't rehash the ASCII part. Just have a look at the Unicode Code Charts.
Kanji will have a Unicode "Script" property of Hani, hiragana will have a "Script" property of Hira, and katakana have a "Script" property of Kana. In Java, you can determine the "Script" property of a character using the Character.UnicodeScript class: http://docs.oracle.com/javase/7/docs/api/java/lang/Character.UnicodeScript.html I don't know if you can determine a character's "Script" property in Javascript.
Of course, most kanji are characters that are also used in Chinese; given a character like 猫, it is impossible to tell whether it's being used as a Chinese character or a Japanese character.
I think what you mean by ASCII code for Japanese is the SBCS (Single Byte Character Set) equivalent in Japanese. For Japanese you only have a MBCS (Multi-Byte Character Sets) that has a combination of single byte character and multibyte characters. So for a Japanese text file saved in MBCS you have non-Japanese characters (english letters and numbers and common non-alphanumeric characters) saved as one byte and Japanese characters saved as two bytes.
Assuming that you are not referring to UNICODE which is a uniform DBCS (Double Byte Character Set) where each character is exactly two bytes. Actually to be more correct lately UNICODE also has multiple DBCS because the character set could not accomodate other character anymore. Some UNICODE character consiste of 4 bytes already having the first two bytes as leading character.
If you are referring to The first one (MBCS) that and not UNICODE then there are a lot of Japanese character set like Shift-JIS (the more popular one). So I suggest that you search Shift-JIS character map. Although there are other Japanese character set map aside from Shift-JIS.