Detailed explanation of WeChat applet array (add, delete, modify, check) and other operation examples

WeChat mini program Array (add, delete, modify, check) and other operations

I am currently working on a demo of a mini program. Since data is not requested from the background, it involves the operation of local data and encounters some pitfalls. This article takes the addition, deletion, modification and query of arrays as an example to share some experiences with novices.

First of all, this is the original data, an array of json.

We try to operate on the data and render it to the page at the same time.

1, Adding data

##After obtaining the data of the form Finally, assemble an object yourself, and then add a piece of data through the push() method. Note that the index of the pushed data is +1, which means that the original index in the array is 0, 1, and 2, and the newly added one is 3. And so on.

If you want to insert data in front, you need to use the array merging operation. The concat() method can choose to merge to the front or back, such as newarray.concat(notes);.

2, Data deletion

There seems to be no remove method in the applet, so I chose the split method to delete it, which is also the one I encountered. pit. notes.splice(id,i) can delete i elements starting from the position where index is id. Everyone knows this. You can understand it by looking at the code. I won’t go into details.

3, Data modification

notes = obj可以把数组中index为i的元素设置为obj。

##Finally, if you want to render to the page while modifying the data, you must remember to use setData method.

this.setData({    notes:notes })

By the way, attach a list of methods for array operations in js. You can try it yourself.

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