题目
字符串中的字母:大写变小写,小写变大写。例如:
100aBcD$#xYz
// 转换为
100AbCd$#XyZ
思路
思路一:正则
思路二:通过 ASCII
代码
/**
* 切换字母大小写(正则表达式)
* @param s str
*/
export function switchLetterCase1(s: string): string {
let res = ''
const length = s.length
if (length === 0) return res
const reg1 = /[a-z]/
const reg2 = /[A-Z]/
for (let i = 0; i < length; i++) {
const c = s[i]
if (reg1.test(c)) {
res += c.toUpperCase()
} else if (reg2.test(c)) {
res += c.toLowerCase()
} else {
res += c
}
}
return res
}
/**
* 切换字母大小写(ASCII 编码)
* @param s str
*/
export function switchLetterCase2(s: string): string {
let res = ''
const length = s.length
if (length === 0) return res
for (let i = 0; i < length; i++) {
const c = s[i]
const code = c.charCodeAt(0)
if (code >= 65 && code <= 90) {
res += c.toLowerCase()
} else if (code >= 97 && code <= 122) {
res += c.toUpperCase()
} else {
res += c
}
}
return res
}
// 功能测试
const str = '100aBcD$#xYz'
console.info(switchLetterCase2(str))
性能测试
// 性能测试
const str = '100aBcD$#xYz100aBcD$#xYz100aBcD$#xYz100aBcD$#xYz100aBcD$#xYz100aBcD$#xYz'
console.time('switchLetterCase1')
for (let i = 0; i < 10 * 10000; i++) {
switchLetterCase1(str)
}
console.timeEnd('switchLetterCase1') // 436ms
console.time('switchLetterCase2')
for (let i = 0; i < 10 * 10000; i++) {
switchLetterCase2(str)
}
console.timeEnd('switchLetterCase2') // 210ms