slice and splice method method

㈠slice () method

⑴ can be used to extract elements from the specified array

   This method does not change the elements of the array , but the package will be taken to the element to return a new array

⑵ syntax:

arrayObject.slice(start,end)

⑶ parameters:

      1. taken start index position, comprising a start index

      2. intercepted end indexed position, does not contain the ending index

                 - The second parameter can be omitted , then the elements will intercept all subsequent index from the start

⑷ index may pass a negative value , a negative value if passed, calculated from back to front

    -1: a penultimate

    -2: penultimate

 

⑸ Example 1: intercepting Index

 

⑹ Example 2: The second parameter can be omitted

 

⑺ Example 3: transmitting a negative index

 

㈡splice () method

⑴ can be used to delete the specified elements in the array

⑵ use splice () will affect the original array , will specify the elements that were removed from the original array

        And will be removed elements returned as the return value

⑶ parameters:

     The first represents the index start position

     The second represents the number of deleted

     The third and beyond. . .

                 You can pass some new elements that will be automatically inserted into the starting position in front of the index

 

⑷splice( )  方法是一个多功能的方法：可以删除元素，可以替换元素，可以在数组的指定位置插入（添加）元素

 

⑸示例1：删除元素

 

⑹示例2：参数所表达的意义

 

⑺示例3：替换元素，指定位置插入元素