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Lua语言中字符串是不可变值(immutable value)
$ cat gsub.lua a = "one string" b = string.gsub(a, "one", "another") print(a) print(b) $ lua gsub.lua one string another string -
长度操作符(length operator) (#)
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连接操作符（..）
$ cat string.lua a = "hello" print(#a) print(#"good bye") print("hello" .. "world") print("result is" .. 3) b = a .. "world" print(a) print(b) $ lua string.lua 5 8 helloworld result is3 hello helloworld -
可以使用一对双引号或单引号来声明字符串常量(literal string)
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多行字符串
page = [[ <html> <body> </body> </html> ]] -
显示地将一个字符串转换成数值
tonumber -
测试
$ lua Lua 5.3.5 Copyright (C) 1994-2018 Lua.org, PUC-Rio > string.rep("abc", 3) abcabcabc > string.reverse("A Long Line!") !eniL gnoL A > string.lower("A Long Line!") a long line! > string.upper("A Long Line!") A LONG LINE! > s = "[in brackets]" > string.sub(s, 2, -2) in brackets > string.sub(s, 1, 1) [ > string.sub(s, -1, -1) ] > > print(string.char(97)) a > i = 99;print(string.char(i, i+1, i+2)) cde > print(string.byte("abc")) 97 > print(string.byte("abc", 2)) 98 > print(string.byte("abc", -1)) 99 > > print(string.byte("abc", 1, 2)) 97 98 > > string.format("x = %d, y = %d", 10, 20) x = 10, y = 20 > string.format("x = %x", 200) x = c8 > string.format("x = 0x%X", 200) x = 0xC8 > string.format("x = %f", 200) x = 200.000000 > tag, title = "h1", "a title" > string.format("<%s>%s</%s>", tag, title, tag) <h1>a title</h1> > > string.format("pi = %.4f", math.pi) pi = 3.1416 > d = 25; m = 6; y = 2019 > string.format("%02d/%02d/%04d", d, m, y) 25/06/2019 > > string.find("hello world", "wor") 7 9 > string.find("hello world", "war") nil > > string.gsub("hello world", "l", ".") he..o wor.d 3 > string.gsub("hello world", "ll", ".") he.o world 1 > string.gsub("hello world", "a", ".") hello world 0 > -
Unicode编码
- 函数
reverse,upper,lower,byte,char不适用与UTF-8字符串 string.format、string.rep适用UTF-8字符串（格式选项%c除外）- 函数
string.len,string.sub可以用于UTF-8字符串，其中索引以字节为单位而不是以字符为单位。 utf8.len()utf8.char()和utf8.codepointutf8.codes
- 函数