10.1.字符串.md

10.1.字符串

类型: String 一个字符串是一个字符序列。

字符编码

使用 .code 属性到一个常量单字节，可以编译它的ASCII字节码：

"#".code // will compile as 35

查看 String API 了解更多关于它的方法的介绍。

10.1.1.字符串字面值

A string literal is a sequence of characters inside a pair of double quotes or single quotes:

var a = "foo";
var b = 'foo';
trace(a == b); // true

The only difference between the two forms is that single-quoted literals allow string interpolation.

Escape sequences

Sequence	Meaning	Unicode codepoint (decimal)	Unicode codepoint (hexadecimal)
\t	horizontal tab (TAB)	9	0x09
\n	new line (LF)	10	0x0A
\r	new line (CR)	13	0x0D
\"	double quote	34	0x22
\'	single quote	39	0x27
\\\\\\\\	backslash	92	0x5C
\NNN	ASCII escape where NNN is 3 octal digits	0 - 127	0x00 - 0x7F
\xNN	ASCII escape where NN is a pair of hexadecimal digits	0 - 127	0x00 - 0x7F
\uNNNN	Unicode escape where NNNN is 4 hexadecimal digits	0 - 65535	0x0000 - 0xFFFF
\u{N...}	Unicode escape where N... is 1-6 hexadecimal digits	0 - 1114111	0x000000 - 0x10FFFF

10.1.2.Unicode

since Haxe 4.0.0

All Haxe targets except Neko support Unicode in strings by default. The compile-time define target.unicode is set on targets where Unicode is supported.

A string in Haxe code represents a valid sequence of Unicode codepoints. Due to differing internal representations of strings across targets, only the basic multilingual plane (BMP) is supported consistently: every BMP Unicode codepoint corresponds to exactly one string character.

It is still possible to work with strings including non-BMP characters on all targets without having to manually decode surrogate pairs by using the Unicode iterators API provided in the standard library.

10.1.3.Encoding

On some targets, the internal representation is UTF-16, which means that non-BMP Unicode codepoints are represented using surrogate pairs. The compile-time define target.utf16 is set when the target uses UTF-16 internally.

Null-bytes in strings

Some Haxe targets disallow null-bytes (Unicode codepoint 0) in strings. Additionally, some Haxe core APIs assume a null-byte terminates strings. To consistently deal with binary data, including null-bytes, use the haxe.io.Bytes API.

Target details

Target	target.unicode	target.utf16	Internal encoding	Null-byte allowed
Flash	yes	yes	UTF-16	no
JavaScript	yes	yes	UTF-16	yes (except in some old browsers)
ActionScript 3	yes	yes	UTF-16	no
C++	yes	yes	ASCII or UTF-16 (if needed)	yes
Java	yes	yes	UTF-16	yes
JVM	yes	yes	UTF-16	yes
C#	yes	yes	UTF-16	yes
Python	yes	no	Latin-1, UCS-2, or UCS-4 (see PEP 393)	yes
Lua	yes	no	UTF-8	yes
PHP	yes	no	binary	yes
Eval	yes	no	UTF-8	yes
Neko	no	no	binary	yes
HashLink	yes	yes	UTF-16	no