[NAME] ALL.dao.type.string.method [TITLE] 字符串方法 [DESCRIPTION] 下面是字符串类型所支持的方法： 1 string( count: int, char = 0 ) => string 2 string( count: int )[index: int => string] => string 3 size( invar self: string, utf8 = false ) => int 4 insert( invar self: string, str: string, pos = 0 ) => string 5 erase( invar self: string, pos = 0, count = -1 ) => string 6 chop( invar self: string, utf8 = 0 ) => string 7 trim( invar self: string, where: enum<head;tail> = $head+$tail, utf8 = 0 ) => string 8 find( invar self: string, str: string, from = 0, reverse = 0 ) => int 9 convert( invar self: string, to: enum<local,utf8,lower,upper> ) => string 10 replace( invar self: string, str1: string, str2: string, index = 0 ) => string 11 expand( invar self: string, invar subs: map<string,string>|tuple<...:string>, 12 spec = "$", keep = 1 ) => string 13 split( invar self: string, sep = "" ) => list<string> 14 iterate( invar self: string, unit: enum<byte,char> = $byte )[char: int, index: int] 15 fetch( invar self: string, pattern: string, group = 0, start = 0, end = -1 ) 16 => string 17 match( invar self: string, pattern: string, group = 0, start = 0, end = -1 ) 18 => tuple<start:int,end:int>|none 19 change( invar self: string, pattern: string, target: string, index = 0, 20 start = 0, end = -1 ) => string 21 capture( invar self: string, pattern: string, start = 0, end = -1 ) => list<string> 22 extract( invar self: string, pattern: string, 23 mtype: enum<both,matched,unmatched> = $matched ) => list<string> 24 scan( invar self: string, pattern: string, start = 0, end = -1 ) 25 [start: int, end: int, state: enum<unmatched,matched> => none|@V] 26 => list<@V> 27 28 offset( invar self: string, charIndex: int ) => int 29 char( invar self: string, charIndex: int ) => string 0.1 初始化方法 除了可用字符串常量生成字符串外，下面的字符串初始化方法 可用来方便灵活地产生字符串。 1 string( count: int, char = 0 ) => string 2 string( count: int )[index: int => string] => string 0.1.1 string(count:int,char=0)=>string 1 string( count: int, char = 0 ) => string 创建并返回一个由"count"个"char"字符组成的字符串。 例子： 1 S1 = string( 5, 'S'[0] ) # SSSSS 2 S2 = string( 3, 0x9053 ) # 道道道 0.1.2 string(count:int)[index:int=>string]=>string 1 string( count: int )[index: int => string] => string 创建并返回一个由代码块的"count"个结果字符串连接而成的字符串。 例子： 1 S1 = string( 5 ){ "S" } # SSSSS 2 S2 = string( 2 ){ "道语言" } # 道语言道语言 3 S3 = string( 6 ){ [index] (string) index } # 012345 0.2 普通方法 下面是可用来方便操作字符串的方法： 1 size( invar self: string, utf8 = false ) => int 2 insert( invar self: string, str: string, pos = 0 ) => string 3 erase( invar self: string, pos = 0, count = -1 ) => string 4 chop( invar self: string, utf8 = 0 ) => string 5 trim( invar self: string, where: enum<head;tail> = $head+$tail, utf8 = 0 ) => string 6 find( invar self: string, str: string, from = 0, reverse = 0 ) => int 7 convert( invar self: string, to: enum<local,utf8,lower,upper> ) => string 8 replace( invar self: string, str1: string, str2: string, index = 0 ) => string 9 expand( invar self: string, invar subs: map<string,string>|tuple<...:string>, 10 spec = "$", keep = 1 ) => string 11 split( invar self: string, sep = "" ) => list<string> 12 iterate( invar self: string, unit: enum<byte,char> = $byte )[char: int, index: int] 13 offset( invar self: string, charIndex: int ) => int 14 char( invar self: string, charIndex: int ) => string 0.2.1 size(invar self:string,utf8=false)=>int 1 size( invar self: string, utf8 = false ) => int 返回字符串里的字节或字符个数。 例子： 例子： 1 S = "ABCDE" 2 len1 = S.size() 3 len2 = "XYZ".size() 为了效率起见，用户也可考虑使用大小操作符%， %S将给出字符串的字符个数。 0.2.2 insert(invar self:string,str:string,pos=0)=>string 1 insert( invar self: string, str: string, pos = 0 ) => string 在"pos"处插入"str"； 返回新字符串。 0.2.3 erase(invar self:string,pos=0,count=-1)=>string 1 erase( invar self: string, pos = 0, count = -1 ) => string 从"pos"处删除"count"字节； 返回新字符串。 0.2.4 chop(invar self:string,utf8=0)=>string 1 chop( invar self: string, utf8 = 0 ) => string 从字符串的末尾切除EOF, '\n', '\r'或'\r\n'。 -- EOF 将先被检查并切除; -- '\n' 将接下来被检查并切除; -- '\r' 将最后被检查并切除; 如果参数"utf8"非零，字符串末尾所有不构成有效UTF-8编码的字符都将被切除。 例子： 1 S1 = "line\n" 2 S2 = S1.chop() 3 4 S3 = "道语言"[:7] 5 S4 = S3.chop( 1 ) # 道语 0.2.5 trim(invarself:string,where:enum<head;tail>=$head+$tail,utf8=0)=>string 1 trim( invar self: string, where: enum<head;tail> = $head+$tail, utf8 = 0 ) => string 将空白字符从字符串首尾剪除。 如果参数"utf8"非零，字符串首尾所有不构成有效UTF-8编码的字符都将被剪除。 例子： 1 S1 = "\tline\n" 2 S2 = S1.trim() # "line" 3 S3 = S1.trim( $head ) # "line\n" 4 5 S4 = "\t道语言"[:7] 6 S5 = S4.trim() # "道语??" 7 S6 = S4.trim( $tail, 1 ) # "\t道语" 0.2.6 find(invar self:string,str:string,from=0,reverse=0)=>int 1 find( invar self: string, str: string, from = 0, reverse = 0 ) => int 从字符串位置"from"开始查找第一个出现的"str"。 如果参数"reverse"为零，向前查找，否则向后查找； 如果"str"没被找到，返回-1；否则返回， 正向查找到的子字符串的第一个字符位置； 或反向查找到的子字符串的最后那个字符的位置。 例子： 1 S1 = "dao programming language and dao virtual machine" 2 P1 = S1.find( "dao" ) # Find the first "dao"; 3 P2 = S2.find( "dao", -1, 1 ) # Find the last "dao"; 0.2.7 convert(invar self:string,to:enum<local,utf8,lower,upper>)=>string 1 convert( invar self: string, to: enum<local,utf8,lower,upper> ) => string 转换字符串。可转换为： -- 系统编码字符串（从UTF-8编码）; -- UTF-8编码字符串（从系统编码）; -- 全小写字符; -- 全大写字符; 例子： 1 S1 = "Dao Language" 2 S2 = S1.convert( $upper ) # DAO LANGUAGE 3 S3 = S1.convert( $lower ) # dao language 0.2.8 replace(invar self:string,str1:string,str2:string,index=0)=>string 1 replace( invar self: string, str1: string, str2: string, index = 0 ) => string 字符串"self"里的子字符串"str1"替换为str2"，并返回新字符串； 如果"index"为零，替换所有的"str1"； 否则，仅替换第"index"个子字符串"str1"； 如果"index"为整数，查找替换将正向进行； 如果"index"为负数，查找替换将反向进行； 例子： 1 S1 = "dao programming language and dao virtual machine" 2 S2 = S1.replace( "dao", "fast", 1 ) # replace the first "dao" with "fast"; 3 S3 = S1.replace( "dao", "fast", -1 ) # replace the last "dao" with "fast"; 4 S4 = S1.replace( "dao", "fast", 0 ) # replace all "dao" with "fast"; 0.2.9 expand(invar self:string,invar subs:map<...>|tuple<...>,spec="$",keep=1)=>... 1 expand( invar self: string, invar subs: map<string,string>|tuple<...:string>, 2 spec = "$", keep = 1 ) => string 将此"self"字符串里的与"subs"里的键字符串匹配的子字符串替换为对应的值字符串， 并将结果以新的 字符串返回。 如果"spec"不为空字符串，那么"subs"里的键字符必须出现在"spec"之后的括号里 才会被替换。替换时 "spec"和括号以及键字符串将被一起替换。 如果"spec"不为空且"keep"为零，那么"subs"里没有对应键的"spec(key)"将被删掉， 否则，将被保留。 例子： 1 S1 = '<a href="@(url)">@(name)</a>' 2 keyvalues = { "url" => "http://daovm.net", "name" => "Dao Website" } 3 S2 = S1.expand( keyvalues, "@" ) # <a href="http://daovm.net">Dao Website</a> 0.2.10 split(invar self:string,sep="")=>list<string> 1 split( invar self: string, sep = "" ) => list<string> 将字符串以字符串"sep"分割，并将结果以字符串列表的形式返回。 如果"sep"为空字符串，"self"字符串将按单个UTF-8字符被分割。 例子： 1 S1 = "dao::io::stdio" 2 L1 = S1.split( "::" ) # { "dao", "io", "stdio" } 3 4 S2 = "道语言" 5 L2 = S2.split() # { "道", "语", "言" } 0.2.11 iterate(invar self:string,unit:enum<byte,char>=$byte)[char:int,index:int] 1 iterate( invar self: string, unit: enum<byte,char> = $byte )[char: int, index: int] 历遍字符串里的每个字节或字符单元，并执行附带的代码块。 如果"unit"为"$byte"，按字节历遍； 如果"unit"为"$char"，按UTF-8字符历遍； 每个不构成有效UTF-8编码的字符将被分别历遍。 代码块的第一个参数可以保存字节或字符的整数编码。而第二个参数则表示 它在字符串里的位置。 例子： 0.2.12 offset(invar self:string,charIndex:int)=>int 1 offset( invar self: string, charIndex: int ) => int 获取第"charIndex"个字符的字节位置。 0.2.13 char(invar self:string,charIndex:int)=>string 1 char( invar self: string, charIndex: int ) => string 获取第"charIndex"个字符。 0.3 Pattern Matching Methods Please see dao.type.string.pattern for more information. 1 fetch( invar self: string, pattern: string, group = 0, start = 0, end = -1 ) 2 => string 3 match( invar self: string, pattern: string, group = 0, start = 0, end = -1 ) 4 => tuple<start:int,end:int>|none 5 change( invar self: string, pattern: string, target: string, index = 0, 6 start = 0, end = -1 ) => string 7 capture( invar self: string, pattern: string, start = 0, end = -1 ) => list<string> 8 extract( invar self: string, pattern: string, 9 mtype: enum<both,matched,unmatched> = $matched ) => list<string> 10 scan( invar self: string, pattern: string, start = 0, end = -1 ) 11 [start: int, end: int, state: enum<unmatched,matched> => none|@V] 12 => list<@V>