Summary of three methods for defining and initializing js two-dimensional array

Summary of three methods for defining and initializing js two-dimensional array_javascript skills

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Release： 2016-05-16 16:57:34

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Method 1: Directly define and initialize. This can be used when the number is small.
var _TheArray = [["0-1","0-2"],["1-1","1-2"],["2-1","2-2"]]

Method 2: Two-dimensional array of unknown length

var tArray = new Array();  //先声明一维
for(var k=0;k<i;k++){    //一维长度为i,i为变量，可以根据实际情况改变

tArray[k]=new Array();  //声明二维，每一个一维数组里面的一个元素都是一个数组；

for(var j=0;j<p;j++){   //一维数组里面每个元素数组可以包含的数量p，p也是一个变量；

tArray[k][j]="";    //这里将变量初始化，我这边统一初始化为空，后面在用所需的值覆盖里面的值
 }
}

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Pass the required values into the defined array
tArray[6][1]=5; //In this way, the value of 5 can be passed into the array, overwriting the initialized empty

Method three: Before this, both of the above methods had problems. Method two, each definition is initialized. Although it can be modified dynamically later, it still does not work

So I tried a method of dynamically passing values into an array

ps: Some interesting phenomena encountered with arrays in practice

I originally thought that the two-dimensional array can directly pass in the value as follows

for(var a=0;a<i;a++){
tArray[a]=(matArray[a],addArray[a]); //matArray[a]和addArray[a]是两个数组，这两个数组直接传入tArray[a]中

};

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The result is that what is received in tArray[a] is the value of the next array, and the content of matArray[a] is ignored. If the position is changed and matArray[a] is behind, then addArray[a] is passed in. ] value.

Think: Simple example:

Copy code The code is as follows:

var a=[1,2];

var b=[];

b[0]=a;//Pass array a into array b as an element of array b

alert(b[0][1]); //2

The above is the simplest two-dimensional array,

Another way to write the above example:

Copy code The code is as follows:

var b=[];

b[0]=[1,2];//Pass the array [1,2] into the b array as an element of the b array

alert(b[0][1]); //2

It can be seen that the above b[0]=[1,2] can be used

Copy code The code is as follows:

for(var a=0;a

tArray[a]=[ matArray[a],addArray[a] ]; In the above example, () is changed to [] to successfully form a two-dimensional array

};

Summary: Method three:

Copy code The code is as follows:

for(var a=0;a

tArray[a]=[ aArray[a],bArray[a],cArray[a]]; You can also add dArray[a],eArray[a]

};

This situation is applicable to the case where several arrays are known and combined into a two-dimensional array

JS creates multi-dimensional array

 <script>
  var allarray=new Array();
  var res="";
  function loaddata()
  {
   for(var i=0;i<3;i++)
 {
 var starth=i*200;
 var strarw=i*200;
 var endh=(i+1)*200;
 var endw=(i+1)*200;
 allarray[i]=new Array();
 allarray[i][0]=new Array();
 allarray[i][1]=new Array();
 allarray[i][0][0]=starth;
 allarray[i][0][1]=strarw;
  allarray[i][1][0]=endh;
 allarray[i][1][1]=endw;
 }
  for(var i=0;i<allarray.length;i++)
  {
    var sh=allarray[i][0][0];
    var sw=allarray[i][0][1]
     var eh=allarray[i][1][0];
    var ew=allarray[i][1][1]
    res+="第"+i+"个坐标的开始坐标是："+sh+","+sw+"结束坐标是："+eh+","+ew+"<br/>";
  }
  document.getElementById("dv").innerHTML=res;
  }
</script>

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