blocks|key|5201165|text|UTF-8是一种多字节编码，可以表示任何Unicode字符。ISO+8859-1是一种单字节编码，可以表示前256个Unicode字符。两者以完全相同的方式对ASCII进行编码。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5201166|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

UTF-8 is a multibyte encoding that can represent any Unicode character. ISO 8859-1 is a single-byte encoding that can represent the first 256 Unicode characters. Both encode ASCII exactly the same way.

blocks|key|5201196|text|维基百科很好地解释了这两种情况：UTF-8与Latin-1+(ISO-8859-1)。前者是可变长度编码，后者是单字节固定长度编码。拉丁-1只编码Unicode字符集的前256个代码点，而UTF-8可用于编码所有代码点。在物理编码级别，只有代码点0-+127进行相同的编码；代码点128+-+255的不同之处在于成为UTF-8的2字节序列，而它们是拉丁语-1的单字节序列。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|5201197|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/Utf-8|1|http://en.wikipedia.org/wiki/Latin-1^0|G|5|0|M|7|1|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]|$A|R|B|S|1|T]]|C|$]]|$1|D|3|-4|5|6|7|U|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]|L|$5|G|H|I|C|$J|M]]]]

Wikipedia explains both reasonably well: <a href="http://en.wikipedia.org/wiki/Utf-8" rel="noreferrer">UTF-8</a> vs <a href="http://en.wikipedia.org/wiki/Latin-1" rel="noreferrer">Latin-1</a> (ISO-8859-1). Former is a variable-length encoding, latter single-byte fixed length encoding.
Latin-1 encodes just the first 256 code points of the Unicode character set, whereas UTF-8 can be used to encode all code points. At physical encoding level, only codepoints 0 - 127 get encoded identically; code points 128 - 255 differ by becoming 2-byte sequence with UTF-8 whereas they are single bytes with Latin-1.

blocks|key|1459586|text|UTF|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1459587|UTF是一系列多字节编码方案，可以表示Unicode代码点，这些代码点可以表示多达2%5E31个大约20亿个字符。UTF-8是一种灵活的编码系统，它使用1到4个字节来表示前2%5E21个大约200万个代码点。|offset|length|1459588|长话短说:任何码位/序数表示低于127的字符，也就是7位安全的ASCII，与大多数其他单字节编码一样，由相同的1字节序列表示。任何码位在127以上的字符都由两个或更多字节的序列表示，其中包含最好解释的编码here的细节。|1459589|ISO-8859|1459590|ISO-8859是一系列单字节编码方案，用于表示可在127到255范围内表示的字母表。这些不同的字母表被定义为ISO-8859-n格式的“部件”，其中最熟悉的可能是“ISO-8859-1+-1”。与UTF-8一样，无论使用哪种编码系列，7位安全的ASCII都不会受到影响。|1459591|这种编码方案的缺点是它无法容纳由超过128个符号组成的语言，也不能同时安全地显示一个以上的符号族。此外，随着UTF的兴起，ISO-8859编码已经失宠。负责这项工作的ISO“工作组”已于2004年解散，将维护工作留给了其上级小组委员会。|1459592|entityMap|0|LINK|mutability|MUTABLE|url|https://en.wikipedia.org/wiki/UTF|1|https://en.wikipedia.org/wiki/Unicode|2|https://en.wikipedia.org/wiki/UTF-8|3|https://en.wikipedia.org/wiki/UTF-8#Examples|4|https://en.wikipedia.org/wiki/ISO/IEC_8859|5|https://en.wikipedia.org/wiki/ISO/IEC_8859-1^0|0|0|3|0|J|7|1|1J|5|2|0|2U|4|3|0|0|0|8|4|2B|A|5|0|0^^$0|@$1|2|3|4|5|6|7|15|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|16|8|@]|9|@$D|17|E|18|1|19]|$D|1A|E|1B|1|1C]|$D|1D|E|1E|1|1F]]|A|$]]|$1|F|3|G|5|6|7|1G|8|@]|9|@$D|1H|E|1I|1|1J]]|A|$]]|$1|H|3|I|5|6|7|1K|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|1L|8|@]|9|@$D|1M|E|1N|1|1O]|$D|1P|E|1Q|1|1R]]|A|$]]|$1|L|3|M|5|6|7|1S|8|@]|9|@]|A|$]]|$1|N|3|-4|5|6|7|1T|8|@]|9|@]|A|$]]]|O|$P|$5|Q|R|S|A|$T|U]]|V|$5|Q|R|S|A|$T|W]]|X|$5|Q|R|S|A|$T|Y]]|Z|$5|Q|R|S|A|$T|10]]|11|$5|Q|R|S|A|$T|12]]|13|$5|Q|R|S|A|$T|14]]]]

<h2>UTF</h2>

<a href="https://en.wikipedia.org/wiki/UTF" rel="noreferrer">UTF</a> is a family of multi-byte encoding schemes that can represent <a href="https://en.wikipedia.org/wiki/Unicode" rel="noreferrer">Unicode</a> code points which can be representative of up to 2^31 [roughly 2 billion] characters. <a href="https://en.wikipedia.org/wiki/UTF-8" rel="noreferrer">UTF-8</a> is a flexible encoding system that uses between 1 and 4 bytes to represent the first 2^21 [roughly 2 million] code points.

Long story short: any character with a code point/ordinal representation below 127, aka 7-bit-safe ASCII is represented by the same 1-byte sequence as most other single-byte encodings. Any character with a code point above 127 is represented by a sequence of two or more bytes, with the particulars of the encoding best explained <a href="https://en.wikipedia.org/wiki/UTF-8#Examples" rel="noreferrer">here</a>.

<h2>ISO-8859</h2>

<a href="https://en.wikipedia.org/wiki/ISO/IEC_8859" rel="noreferrer">ISO-8859</a> is a family of single-byte encoding schemes used to represent alphabets that can be represented within the range of 127 to 255. These various alphabets are defined as "parts" in the format ISO-8859-n, the most familiar of these likely being <a href="https://en.wikipedia.org/wiki/ISO/IEC_8859-1" rel="noreferrer">ISO-8859-1</a> aka 'Latin-1'. As with UTF-8, 7-bit-safe ASCII remains unaffected regardless of the encoding family used.

The drawback to this encoding scheme is its inability to accommodate languages comprised of more than 128 symbols, or to safely display more than one family of symbols at one time. As well, ISO-8859 encodings have fallen out of favor with the rise of UTF. The ISO "Working Group" in charge of it having disbanded in 2004, leaving maintenance up to its parent subcommittee.

blocks|key|1672380|text|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1672381|ASCII码:7位。128码points.|unordered-list-item|1672382|ISO-8859-1:+8位。256个码位。|1672383|UTF-8:+8-32位(1-4字节)。1,112,064个码位。|1672384|1672385|ISO-8859-1和UTF-8都向后兼容ASCII，但UTF-8不向后兼容ISO-8859-1：|1672386|#!/usr/bin/env+python3

c+=+chr(0xa9)
print(c)
print(c.encode('utf-8'))
print(c.encode('iso-8859-1'))|code-block|syntax|javascript|1672387|输出：|1672388|©
b'\xc2\xa9'
b'\xa9'|1672389|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|-4|4|5|6|V|7|@]|8|@]|9|$]]|$1|A|3|B|4|C|6|W|7|@]|8|@]|9|$]]|$1|D|3|E|4|C|6|X|7|@]|8|@]|9|$]]|$1|F|3|G|4|C|6|Y|7|@]|8|@]|9|$]]|$1|H|3|-4|4|5|6|Z|7|@]|8|@]|9|$]]|$1|I|3|J|4|5|6|10|7|@]|8|@]|9|$]]|$1|K|3|L|4|M|6|11|7|@]|8|@]|9|$N|O]]|$1|P|3|Q|4|5|6|12|7|@]|8|@]|9|$]]|$1|R|3|S|4|M|6|13|7|@]|8|@]|9|$N|O]]|$1|T|3|-4|4|5|6|14|7|@]|8|@]|9|$]]]|U|$]]

<ul>
<li>ASCII: 7 bits. 128 code points.</li>
<li>ISO-8859-1: 8 bits. 256 code points.</li>
<li>UTF-8: 8-32 bits (1-4 bytes). 1,112,064 code points.</li>
</ul>

Both ISO-8859-1 and UTF-8 are backwards compatible with ASCII, but UTF-8 is not backwards compatible with ISO-8859-1:

<pre><code>#!/usr/bin/env python3

c = chr(0xa9)
print(c)
print(c.encode('utf-8'))
print(c.encode('iso-8859-1'))
</code></pre>

Output:

<pre><code>©
b'\xc2\xa9'
b'\xa9'
</code></pre>

blocks|key|5201242|text|ISO-8859-1是20世纪80年代的遗留标准。它只能表示256个字符，因此仅适用于西方世界的某些语言。即使对于许多受支持的语言，也缺少一些字符。如果你用这种编码创建一个文本文件，并尝试复制/粘贴一些中文字符，你会看到奇怪的结果。因此，换句话说，不要使用它。Unicode已经占领了世界，UTF-8几乎就是这些天的标准，除非你有一些遗留的原因(比如HTTP头，它需要兼容所有东西)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5201243|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

ISO-8859-1 is a legacy standards from back in 1980s. It can only represent 256 characters so only suitable for some languages in western world. Even for many supported languages, some characters are missing. If you create a text file in this encoding and try copy/paste some Chinese characters, you will see weird results. So in other words, don't use it. Unicode has taken over the world and UTF-8 is pretty much the standards these days unless you have some legacy reasons (like HTTP headers which needs to compatible with everything).

blocks|key|5201517|text|要认识到的更重要的一件事是:如果你看到iso-8859-1，它可能指的是Windows-1252而不是ISO/IEC+8859-1。它们的不同之处在于0x80-0x9F，其中ISO8859-1具有C1控制代码，而Windows-1252具有有用的可见字符。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5201518|例如，ISO8859-1使用0x85作为控制字符(在Unicode、U%2B0085、中)，而Windows-1252使用水平省略号(在Unicode中，U%2B2026水平省略号，…)。|5201519|WHATWG+Encoding+spec+(超文本标记语言使用的)明确声明iso-8859-1是windows-1252的标签，而web浏览器并不以任何方式支持ISO8859-1:超文本标记语言规范规定必须支持编码规范中的所有编码，而且不能更多。|5201520|同样值得注意的是，HTML数字字符引用基本上使用Windows1252作为8位值，而不是Unicode代码点；根据https://html.spec.whatwg.org/#numeric-character-reference-end-state，&#x85;将生成U%2B2026而不是U%2B0085。|5201521|entityMap|0|LINK|mutability|MUTABLE|url|https://en.wikipedia.org/wiki/Windows-1252|1|https://en.wikipedia.org/wiki/ISO/IEC_8859-1|2|https://encoding.spec.whatwg.org/#names-and-labels|3|https://html.spec.whatwg.org/#numeric-character-reference-end-state^0|J|A|10|C|0|1F|E|1|0|2F|1|0|11|A|1C|C|0|K|2|0|3H|6|1L|1V|3|0^^$0|@$1|2|3|4|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@$9|12|A|13|1|14]|$9|15|A|16|1|17]]|E|$]]|$1|F|3|G|5|6|7|18|8|@$9|19|A|1A|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|1B|8|@$9|1C|A|1D|B|C]|$9|1E|A|1F|B|C]]|D|@$9|1G|A|1H|1|1I]]|E|$]]|$1|J|3|K|5|6|7|1J|8|@$9|1K|A|1L|B|C]]|D|@$9|1M|A|1N|1|1O]]|E|$]]|$1|L|3|-4|5|6|7|1P|8|@]|D|@]|E|$]]]|M|$N|$5|O|P|Q|E|$R|S]]|T|$5|O|P|Q|E|$R|U]]|V|$5|O|P|Q|E|$R|W]]|X|$5|O|P|Q|E|$R|Y]]]]

One more important thing to realise: if you see <code>iso-8859-1</code>, it probably refers to <a href="https://en.wikipedia.org/wiki/Windows-1252" rel="noreferrer">Windows-1252</a> rather than <a href="https://en.wikipedia.org/wiki/ISO/IEC_8859-1" rel="noreferrer">ISO/IEC 8859-1</a>. They differ in the range 0x80–0x9F, where ISO 8859-1 has the C1 control codes, and Windows-1252 has useful visible characters instead.

For example, ISO 8859-1 has 0x85 as a control character (in Unicode, U+0085, ``), while Windows-1252 has a horizontal ellipsis (in Unicode, U+2026 HORIZONTAL ELLIPSIS, <code>…</code>).

The <a href="https://encoding.spec.whatwg.org/#names-and-labels" rel="noreferrer">WHATWG Encoding spec</a> (as used by HTML) expressly declares <code>iso-8859-1</code> to be a label for <code>windows-1252</code>, and web browsers do not support ISO 8859-1 in any way: the HTML spec says that all encodings in the Encoding spec must be supported, and no more.

Also of interest, HTML numeric character references essentially use Windows-1252 for 8-bit values rather than Unicode code points; per <a href="https://html.spec.whatwg.org/#numeric-character-reference-end-state" rel="noreferrer">https://html.spec.whatwg.org/#numeric-character-reference-end-state</a>, <code>&amp;#x85;</code> will produce U+2026 rather than U+0085.

blocks|key|1455439|text|从另一个角度来看，unicode和ascii编码都无法读取的文件，因为它们中有一个字节0xc0，似乎可以被iso-8859-1正确读取。需要注意的是，文件中当然不应该包含unicode字符。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1455440|entityMap^0|17|4|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

From another perspective, files that both unicode and ascii encodings fail to read because they have a byte <code>0xc0</code> in them, seem to get read by iso-8859-1 properly. The caveat is that the file shouldn't have unicode characters in it of course.

blocks|key|5201337|text|我研究这个问题的原因是从这个角度来看，它们在哪些方面是兼容的。存储在utf8数据存储中的Latin1字符集(iso-8859)是100%25兼容的。所有ascii+&+extended-ascii字符都将存储为单字节。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5201338|相反，从utf8到Latin1字符集可能工作，也可能不工作。如果有任何2字节的字符(超出扩展ascii+255的字符)，它们将不会存储在Latin1数据存储中。|5201339|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

My reason for researching this question was from the perspective, is in what way are they compatible. Latin1 charset (iso-8859) is 100% compatible to be stored in a utf8 datastore. All ascii &amp; extended-ascii chars will be stored as single-byte. 

Going the other way, from utf8 to Latin1 charset may or may not work. If there are any 2-byte chars (chars beyond extended-ascii 255) they will not store in a Latin1 datastore.

What is the difference between <a href="https://en.wikipedia.org/wiki/UTF-8" rel="noreferrer">UTF-8</a> and <a href="https://en.wikipedia.org/wiki/ISO/IEC_8859-1" rel="noreferrer">ISO-8859-1</a>?

问UTF-8和ISO-8859-1有什么区别？
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