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[js] 第5天 写一个把字符串大小写切换的方法#15
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@haizhilin2013

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@haizhilin2013
haizhilin2013
opened on Apr 20, 2019
Collaborator

第5天 写一个把字符串大小写切换的方法

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haizhilin2013
added
jsJavaScript
on Apr 20, 2019
undefinedYu

undefinedYu commented on Apr 27, 2019

@undefinedYu
undefinedYu
on Apr 27, 2019
Contributor

var reversal = function(str){
var newStr = '';
if(Object.prototype.toString.call(str).slice(8,-1) !== 'String'){
alert("请填写字符串")
}else{
for(var i=0;i<str.length;i++){
newStr += ((str.charCodeAt(i)>96 && str.substr(i,1).toUpperCase()) || str.substr(i,1).toLowerCase());
}
}
return newStr;
}

linghucq1

linghucq1 commented on May 8, 2019

@linghucq1
linghucq1
on May 8, 2019 · edited by linghucq1
function caseConvert(str) {
  return str.split('').map(s => {
    const code = s.charCodeAt();
    if (code < 65 || code > 122 || code > 90 && code < 97) return s;
    
    if (code <= 90) {
      return String.fromCharCode(code + 32)
    } else {
      return String.fromCharCode(code - 32)
    }
  }).join('')
}

console.log(caseConvert('AbCdE')) // aBcDe 

function caseConvertEasy(str) {
  return str.split('').map(s => {
    if (s.charCodeAt() <= 90) {
      return s.toLowerCase()
    }
    return s.toUpperCase()
  }).join('')
}

console.log(caseConvertEasy('AbCxYz')) // aBcXyZ
lantian1024

lantian1024 commented on May 15, 2019

@lantian1024
lantian1024
on May 15, 2019 · edited by lantian1024
function caseConvert(str){
    return str.replace(/([a-z]*)([A-Z]*)/g, (m, s1, s2)=>{
	return `${s1.toUpperCase()}${s2.toLowerCase()}`
    })
}
caseConvert('AsA33322A2aa') //aSa33322a2AA
fuiiiiiii

fuiiiiiii commented on May 22, 2019

@fuiiiiiii
fuiiiiiii
on May 22, 2019
let str = 'aBcDeFgH'
let arr = []
for(let item of str) {
  if (item === item.toUpperCase()) {
    item = item.toLowerCase()
  } else {
    item = item.toUpperCase()
  }
  arr.push(item)
}
let newStr = arr.join('')
console.log(newStr)
// AbCdEfGh
likeke1997

likeke1997 commented on Jun 5, 2019

@likeke1997
likeke1997
on Jun 5, 2019
function toggle(str) {
    var result = str.split('');
    result.forEach(function(e, i, a) {
        a[i] = e === e.toUpperCase() ? a[i] = a[i].toLowerCase() : a[i] = a[i].toUpperCase()
    });
    return result.join('');
}
var result = toggle('ifYouAreMyWorld');
console.log(result); // IFyOUaREmYwORLD
MartinsYong

MartinsYong commented on Jun 21, 2019

@MartinsYong
MartinsYong
on Jun 21, 2019
function caseTransform (str) {
	let transformed = '';
	for (let v of str) {
		const charCode = v.charCodeAt();
		if (charCode >= 97 && charCode <= 122) {
			transformed += v.toUpperCase();
		}
		else if (charCode >= 65 && charCode <= 90) {
			transformed += v.toLowerCase();
		}
		else {
			transformed += v;
		}
	}
	return transformed;
}
Konata9

Konata9 commented on Jul 2, 2019

@Konata9
Konata9
on Jul 2, 2019
const convertCase = (str) =>
  str
    .split("")
    .map((s) => (/[A-Z]/.test(s) ? s.toLowerCase() : s.toUpperCase()))
    .join("");

console.log(convertCase('AbCdE'))
console.log(convertCase('aaabbbCCCDDDeeefff'))
console.log(convertCase('aBcDe'))
Azathoth-H

Azathoth-H commented on Jul 12, 2019

@Azathoth-H
Azathoth-H
on Jul 12, 2019
const upperOrlower = (str) => str.split('').reduce((acc, x)=> acc+= x == x.toLocaleUpperCase()? x.toLocaleLowerCase(): x.toLocaleUpperCase(), '')
    upperOrlower("what's THIS ?") // WHAT'S this ?
seho-dev

seho-dev commented on Jul 14, 2019

@seho-dev
seho-dev
on Jul 14, 2019

学习到了，借鉴到了;

function test(str) {
return str.replace(/([a-z])([A-Z])/g, (m, s1, s2) => {
return ${s1.toUpperCase()}${s2.toLowerCase()};
});
}

function test2(str) {
let arr = [];
for (let x of str) {
if (x === x.toUpperCase()) {
x = x.toLowerCase();
} else {
x = x.toUpperCase();
}
arr.push(x);
}
return arr.join("");
}

console.log(test("a6M3cH"));

shufangyi

shufangyi commented on Jul 18, 2019

@shufangyi
shufangyi
on Jul 18, 2019
const exchangeUpAndLow = str =>
  typeof str === 'string'
    ? str.replace(/[A-Za-z]/g, char =>
        char.charCodeAt(0) <= 90
          ? char.toLocaleLowerCase()
          : char.toLocaleUpperCase()
      )
    : str
wyx2014

wyx2014 commented on Jul 24, 2019

@wyx2014
wyx2014
on Jul 24, 2019
function change2Char(str) {
  if(typeof str !== 'string'){
    return '请输入字符串';
   }
   return str.split('').map(function (item) {
       return /^[a-z]$/.test(item)?item.toUpperCase():item.toLowerCase();
   }).join('');
gu-xionghong

gu-xionghong commented on Jul 25, 2019

@gu-xionghong
gu-xionghong
on Jul 25, 2019
function caseConvert(str) {
  return str.replace(/([a-z])?([A-Z]?)/g, function(m, $1, $2) {
    let s = ''
    s += $1 ? $1.toUpperCase() : ''
    s += $2 ? $2.toLowerCase() : ''
    return s
  })
}

caseConvert('asd__BBB_cDe')
IanSun

IanSun commented on Jul 26, 2019

@IanSun
IanSun
on Jul 26, 2019
function reverseCharCase ( string = `` ) {
  return Array.prototype.reduce.call(
    string,
    ( string, char ) =>
      string += `\u0040` < char && `\u005b` > char ?
        char.toLowerCase() :
        `\u0060` < char && `\u007b` > char ?
          char.toUpperCase() :
          char,
    ``,
  );
}
wsb260

wsb260 commented on Jul 31, 2019

@wsb260
wsb260
on Jul 31, 2019 · edited by wsb260
// 1.test() 方法用于检测一个字符串是否匹配某个模式,返回Boolean值 
// 2.toUpperCase() 转换成大写,toLowerCase()转换成小写

function changeStr(str){
  let ary = [];
  let newStr = '';
  if(!str||str === ''||typeof str !== 'string'){
    return false;
  }
  ary = str.split("");
  ary.map(item => {
    newStr += /[A-Z]/.test(item) ? item.toLowerCase() : item.toUpperCase();
  })
  console.log(newStr)
}

changeStr('aAbBcC') // 输出:AaBbCb

//$1、$2、...、$99与 regexp 中的第 1 到第 99 个子表达式相匹配的文本
//function（a,b,c）一共可以传入3个参数，第一个为匹配到的字符串，第二个为匹配字符串的起始位置，第三个为调用replace方法的字符串本身,(非全局匹配的情况下/g),下例为多组匹配,s1,s2分别对应$1,$2
function caseConvert(str){
  return str.replace(/([a-z]*)([A-Z]*)/g, function(m,s1,s2){
    return s1.toUpperCase() + s2.toLowerCase()
  })
}
console.log(caseConvert('aSa')) //AsA

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          [js] 第5天 写一个把字符串大小写切换的方法 · Issue #15 · haizlin/fe-interview