--lua中字符串索引從前往后是1,2,……，從后往前是-1，-2……。
--string庫(kù)中所有的function都不會(huì)直接操作字符串，只返回一個(gè)結(jié)果。
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【基本函數(shù)】
函數(shù)描述示例結(jié)果
len計(jì)算字符串長(zhǎng)度string.len("abcd")4
rep返回字符串s的n個(gè)拷貝string.rep("abcd",2)abcdabcd
lower返回字符串全部字母大寫string.lower("AbcD")abcd
upper返回字符串全部字母小寫string.upper("AbcD")ABCD
format返回一個(gè)類似printf的格式化字符串string.format("the value is:%d",4)the value is:4
subreturns substring from index i to j of sstring.sub("abcd",2)bcd
string.sub("abcd",-2)cd
string.sub("abcd",2,-2)bc
string.sub("abcd",2,3)bc
find在字符串中查找string.find("cdcdcdcd","ab")nil
string.find("cdcdcdcd","cd")1?2
string.find("cdcdcdcd","cd",7)7?8
gsub在字符串中替換string.gsub("abcdabcd","a","z");zbcdzbcd?2
string.gsub("aaaa","a","z",3);zzza?3
byte返回字符的整數(shù)形式string.byte("ABCD",4)68
char將整型數(shù)字轉(zhuǎn)成字符并連接string.char(97,98,99,100)abcd
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【基本模式串】
字符類描述示例結(jié)果
.任意字符string.find("",".")nil
%s空白符string.find("ab?cd","%s%s")3?4
%S非空白符string.find("ab?cd","%S%S")1?2
%p標(biāo)點(diǎn)字符string.find("ab,.cd","%p%p")3?4
%P非標(biāo)點(diǎn)字符string.find("ab,.cd","%P%P")1?2
%c控制字符string.find("abcd\t\n","%c%c")5?6
%C非控制字符string.find("\t\nabcd","%C%C")3?4
%d數(shù)字string.find("abcd12","%d%d")5?6
%D非數(shù)字string.find("12abcd","%D%D")3?4
%x十六進(jìn)制數(shù)字string.find("efgh","%x%x")1?2
%X非十六進(jìn)制數(shù)字string.find("efgh","%X%X")3?4
%a字母string.find("AB12","%a%a")1?2
%A非字母string.find("AB12","%A%A")3?4
%l小寫字母string.find("ABab","%l%l")3?4
%L大寫字母string.find("ABab","%L%L")1?2
%u大寫字母string.find("ABab","%u%u")1?2
%U非大寫字母string.find("ABab","%U%U")3?4
%w字母和數(shù)字string.find("a1()","%w%w")1?2
%W非字母非數(shù)字string.find("a1()","%W%W")3?4
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【轉(zhuǎn)義字符%】
字符類描述示例結(jié)果
%轉(zhuǎn)義字符string.find("abc%..","%%")4?4
string.find("abc..d","%.%.")4?5
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【用[]創(chuàng)建字符集，"-"為連字符，"^"表示字符集的補(bǔ)集】
字符類描述示例結(jié)果
[01]匹配二進(jìn)制數(shù)string.find("32123","[01]")3?3
[AB][CD]匹配AC、AD、BC、BDstring.find("ABCDEF","[AB][CD]")2?3
[[]]匹配一對(duì)方括號(hào)[]string.find("ABC[]D","[[]]")4?5
[1-3]匹配數(shù)字1-3string.find("312","[1-3][1-3][1-3]")1?3
[b-d]匹配字母b-dstring.find("dbc","[b-d][b-d][b-d]")1?3
[^%s]匹配任意非空字符string.find("?a?","[^%s]")3?3
[^%d]匹配任意非數(shù)字字符string.find("123a","[^%d]")4?4
[^%a]匹配任意非字母字符string.find("abc1","[^%a]")4?4
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【用"()"進(jìn)行捕獲】
字符類描述示例結(jié)果
()捕獲字符串string.find("12ab","(%a%a)")3?4?ab
string.find("ab12","(%d%d)")3?4?12
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【模式修飾符】
修飾符描述示例結(jié)果
+表示1個(gè)或多個(gè)，匹配最多個(gè)string.find("aaabbb","(a+b)")1?4?aaab
string.find("cccbbb","(a+b)")nil
-表示0個(gè)或多個(gè)，匹配最少個(gè)string.find("zzxyyy","(xy-)")3?3?x
string.find("zzzyyy","(x-y)")4?4?y
*表示0個(gè)或多個(gè)，匹配最多個(gè)string.find("mmmnnn","(m*n)")1?4?mmmb
string.find("lllnnn","(m*n)")4?4?n
?表示0個(gè)或1個(gè)string.find("aaabbb","(a?b)")3?4?ab
string.find("cccbbb","(a?b)")4?4?b
