Jquery遍历筛选数组的几种方法和遍历解析json对象,Map()方法详解以及数组中查询某值是否存在

// 1.jquery grep()筛选遍历数组(可以得到反转的数组)
  var array = [1,5,9,3,12,4,48,98,4,75,2,10,11];
  var filterArray = $.grep(array,(currentValue) => {
    return currentValue > 10;
  });
  console.log(`${filterArray}---${filterArray.length}`);//12,48,98,75,11---5
  var filterReverse = $.grep(array,(currentValue) => {
    return currentValue > 10;
  },true);
  console.log(`${filterReverse}---${filterReverse.length}`);//1,5,9,3,4,4,2,10---8
 
  // for(var i=0;i<filterArray.length;i++){
  //   console.log(filterArray[i]);
  // }
  for(key in filterArray){
    console.log(filterArray[key])
  }

var ages = [32, 33, 16, 40, 45, 98, 12, 35, 8,16];
  var filterAges = ages.filter((currentValue,index,ages) => {
    return currentValue > 20;
  })
  console.log(filterAges);//[32, 33, 40, 45, 98, 35]
  for(key in filterAges){
    console.log(filterAges[key])
  }

var anObject = {one:1,two:2,three:3};//对json数组each
  $.each(anObject,function(name,value) {
    console.log(`${name}---${value}`)
  });
  var anArray = ['one','two','three'];
  $.each(anArray,function(n,value){
     console.log(`${n}---${value}`)
  });

var forArray = ['mu','zi','muzi','digbig','muzidigbig'];
  forArray.forEach((currentValue,index,forArray) => {
    console.log(`${index}---${currentValue}`)
  })

var strings = ['0','1','2','3','4','S','6'];
  var values = $.map(strings,function(value){
      var result = new Number(value);
      return isNaN(result) ? null:result;//isNaN:is Not a Number的缩写
    });
  for (key in values) {
    console.log(values[key]);
  }

var iArray = ['one','two','three','two'];
  var index = $.inArray('two',anArray);
  console.log(`返回该值在数组中的键值:${index}`);//返回该值在数组中的键值，返回 1
  console.log(`返回该键在数组中的值:${iArray[index]}`);//two

var iArray = ['one','two','three','two'];
  var indexOf = iArray.indexOf('two');
  console.log(indexOf);//1

var iArray = ['one','two','three','two'];
  var index = iArray.includes('two');
  console.log(index);//true

var json = [{dd:'SB',AA:'东东',re1:123},{cccc:'dd',lk:'1qw'}];
for(var i=0,l=json.length;i<l;i++){
  for(var key in json[i]){
  console.log(`${key}:${json[i][key]}`);
  }
}

var obj ={'name':'冯娟','password':'123456','department':'技术部','sex':'女','old':30};

var obj ={'name':'冯娟','password':'123456','department':'技术部','sex':'女','old':30};
var str = '';
for(var p in obj){
  str += obj[p]+',';
//  return str;
}
console.log(str);//冯娟,123456,技术部,女,30,

$("p").append( $("input").map(function(){
 return $(this).val();
}).get().join(", ") );

<form method="post" action="">
 <fieldset>
  <div>
   <label for="two">2</label>
   <input type="checkbox" value="2" id="two" name="number[]">
  </div>
  <div>
   <label for="four">4</label>
   <input type="checkbox" value="4" id="four" name="number[]">
  </div>
  <div>
   <label for="six">6</label>
   <input type="checkbox" value="6" id="six" name="number[]">
  </div>
  <div>
   <label for="eight">8</label>
   <input type="checkbox" value="8" id="eight" name="number[]">
  </div>
 </fieldset>
</form>

$(':checkbox').map(function() {
 return this.id;
}).get().join(',');