The splice () method of the Javascript--array array deletes, inserts, replaces __java

The splice () method of array arrays is also a very powerful way to delete, insert, replace

It should be noted that the splice () method modifies the original array directly

I. The use of deletion

Grammar: Array.splice (starti,n);

Starti refers to where to start (not including Starti)

n refers to the number of items that need to be deleted

[HTML] view plain copy <script> var array=[1,2,3,4,5];       Array.splice (3,2);   Console.log (array); </script>

Result: [1,2,3]

Here is a small extension: In fact, the deleted elements can be received with a variable, the received variable can be used as a mosaic array

[HTML]View plain copy <script> var array=[1,2,3,4,5];       var deletes =array.splice (3,2);       Console.log (deletes);   Console.log (array); </script>

Results: [4,5] [1,2,3]

We will delete the elements after the original array is spliced back

[HTML]View plain copy <script> var array=[1,2,3,4,5];       var deletes =array.splice (3,2);       Console.log (deletes);       Console.log (array);       Array=array.concat (deletes);   Console.log (array); </script>

Results: [4,5] [1,2,3] [1,2,3,4,5]

Second, the use of insertion

Syntax: Array.splice (starti,0, value 1, value 2 ...);

Starti: Where to insert, the value of the original Starti position to move backward

0: Deletes 0 elements, because both inserts and replacements are expanded by the deletion function.

Value 1, value 2: The value that needs to be inserted

[HTML]View plain copy <script> var array=[1,2,3,4,5];       Array.splice (2,0,123,456);   Console.log (array); </script> results: [1,2,123,456,3,4,5]

Third, the use of substitution

Syntax: Array.splice (starti,n, value 1, value 2);

The principle is the same as the use of inserts

The real thing is: Delete the n elements in the Starti position, then insert the value 1 in this position, and the value 2, you can replace

Values that were originally deleted

[HTML] view plain copy <span style= "FONT-SIZE:24PX;"       ><script> var array=[1,2,3,4,5];       Array.splice (2,2,123,456);   Console.log (array); </script></span>