JS array creation and CONCAT () split () slice () The use of the method _javascript skills

The use of JS array creation and CONCAT () split () Slice ()

1 var a = new Array ();

2 var b=new Array;

3 var c= new Array ("Red", "green", "white");

Alert (b.length)  //20

Arrays can grow or decrease as needed. So

C[3] = "purple";

Alert (c.length)//4

If

C[25]= "Purple"/is filled with null 

alert (c.length) from 3 to 24//26

You can also define an array object in literal notation, that is, by using square brackets and separating values with commas.

var d =["Red", "green", "white"];

Alert (d.length)  //3

d[25]= "PURPLR"

alert (d.length);//26

Note In this example, the array class is not explicitly used. The square brackets imply that the values are stored in the array object, and that the array declared in this way is the same as the array declared in the traditional way

The array object overrides the ToString () method and the ValueOf () method. Returns a special string.

var e =["Red", "green", "white"];

Alert (e.tostring ());  "Red,green,white"

alert (e.valueof ());  Ditto

Join ()

Alert (E.join ("-spring-"))  //"Red-spring-green-spring-white"

Split () method, string converts itself to an array

var s= "A,b,c";

var ss=s.split (",");//returns 3 arrays

Character-by parsing strings

var s= "Green"

var ss=s.split ("")

alert (ss.tostring ())  //Back to "G,r,e,e,n"

The array object has a method of two string classes, that is, the concat () and the Slice () method; The Concat method handles the array as if it were a string, and the parameter is appended to the end of the array, and the returned function value is the new Array object

The slice () method is the same as the string slice () method, returns a new array with a specific item: if there is only one argument, the modification returns all items starting at that position to the end of the array, and if there are two parameters, it returns all the values between the first position and the second bit. Items that do not include a second position

var s=["A", "B", "C"];

var scon=s.concat ("D", "E");

Alert (scon.tostring ())  //"A,b,c,d,e"

alert (s.tostring ())  //"A,b,c"

var s1=s.slice (1)  //s1 to " B,c " 

var s2=s.slice (0,2)//s2 to" A,b "

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