打印和编程

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字数统计: 457 字 | 阅读时长 ≈ 2 分钟

打印

promise

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console.log('a')
setTimeout(() =>{
  console.log('b')
},0)
new Promise((resolve)=>{
  console.log('c')
  resolve()
}).then(()=>{
  console.log('d')
})
new Promise((resolve)=>{
  console.log('e')
  resolve()
}).then(()=>{
  console.log('f')
})
setTimeout(() =>{
  console.log('g')
},0)
console.log('h')
//acehdfbg

this

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var obj = {
  func: function(){
    console.log(this)
  }
}
var func1 = obj.func
obj.func()
func1()
//{func: ƒ}func: ƒ ()arguments: nullcaller: nulllength: 0name: "func"prototype: {constructor: ƒ}__proto__: ƒ ()[[FunctionLocation]]: VM2010:2[[Scopes]]: Scopes[1]__proto__: Object
//Window {postMessage: ƒ, blur: ƒ, focus: ƒ, close: ƒ, parent: Window, …}

代码题

匹配qq号

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String regex = "[1-9][0-9]{4,14}"; // 第一位1-9之间的数字，第二位0-9之间的数字，数字范围4-14个之间

在一段英文中找出出现频率最高的单词

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function counts(article){
  article = article.trim().toUpperCase();     
  var array = article.match(/[A-z]+/g);    
  article = " "+array.join("  ")+" ";     
  var max = 0,word,num = 0,maxword="";     
  for(var i = 0; i < array.length; i++) {                
    word = new RegExp(" "+array[i]+" ",'g');     
    num = article.match(word).length;     
    if(num>max){         	
      max=num;         
      maxword = array[i];     
    }    
  }    
  console.log(maxword+" "+max); 
} 
counts("Age has reached the end of the beginning of a word. May be guilty in his seems to passing a lot of different life became the appearance of the same day;");

数组去重

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// 最简单数组去重法 
/* 
* 新建一新数组，遍历传入数组，值不在新数组就push进该新数组中 
*  IE8以下不支持数组的indexOf方法 * 
* */ 
function uniq(array){     
  var temp = []; //一个新的临时数组    
  for(var i = 0; i < array.length; i++){        
    if(temp.indexOf(array[i]) == -1){             
      temp.push(array[i]);         
    }    
  }     
  return temp; 
}  
var aa = [1,2,2,4,9,6,7,5,2,3,5,6,5]; 
console.log(uniq(aa));

千位符分割

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(1234567.8).toLocaleString() "1,234,567.8"

字符串反转

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string.split('').reverse().join('')

img

字符串变数组

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split('')

数组变字符串

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join('')