What are the functions for changing arrays in Vue?

Vue is a progressive JavaScript framework for building interactive web interfaces that offers the advantages of ease of use and rapid development. In Vue, we usually encounter situations where we need to change an array. For this need, Vue provides several convenient functions to change the array.

1. push method

The push method is one of the most commonly used array modification functions in Vue, which can add one or more elements to the end of the array. The syntax is as follows:

array.push(element1, ..., elementX)

Among them, element1 to elementX are the elements to be added, which can be of any type. The array will dynamically grow according to the parameters passed in. When using the push method, Vue will automatically update the view so that the user can see the added results.

For example, we have the following Vue component:

<template>
  <div>
    <ul>
      <li v-for="item in items">{{ item }}</li>
    </ul>
    <button @click="addItem">添加</button>
  </div>
</template>

<script>
export default {
  data() {
    return {
      items: ["苹果", "西瓜", "香蕉"]
    };
  },
  methods: {
    addItem() {
      this.items.push("橘子");
    }
  }
};
</script>

In this component, we use the v-for directive to loop through each element in the items array and add a " Add" button. When the user clicks the button, the addItem method will be called, using the push method to add "oranges" to the end of the array. Vue will automatically update the view to allow users to see the added results.

2. pop method

The pop method is opposite to the push method. It can delete the last element in the array and return the element. The syntax is as follows:

array.pop()

When using the pop method, Vue will also automatically update the view and present the deleted results to the user.

For example, we add a "delete" button to the Vue component above:

<template>
  <div>
    <ul>
      <li v-for="item in items">{{ item }}</li>
    </ul>
    <button @click="addItem">添加</button>
    <button @click="delItem">删除</button>
  </div>
</template>

<script>
export default {
  data() {
    return {
      items: ["苹果", "西瓜", "香蕉"]
    };
  },
  methods: {
    addItem() {
      this.items.push("橘子");
    },
    delItem() {
      this.items.pop();
    }
  }
};
</script>

In this component, we add a "delete" button, and the delItem method will delete the last item in the array. An element is deleted. When the user clicks the "Delete" button, Vue will automatically update the view to display the deleted results.

3. shift method

Similar to the pop method, the shift method can also delete the first element in the array and return the element. The syntax is as follows:

array.shift()

When using the shift method, Vue will also automatically update the view and present the deleted results.

For example, we modify the above Vue component to insert it at the beginning of the array when adding, and delete the beginning of the array when deleting:

<template>
  <div>
    <ul>
      <li v-for="item in items">{{ item }}</li>
    </ul>
    <button @click="addItem">添加</button>
    <button @click="delItem">删除</button>
  </div>
</template>

<script>
export default {
  data() {
    return {
      items: ["苹果", "西瓜", "香蕉"]
    };
  },
  methods: {
    addItem() {
      this.items.unshift("橘子");
    },
    delItem() {
      this.items.shift();
    }
  }
};
</script>

In this component, we use the unshift method to add elements to the array At the beginning, the shift method deletes the elements at the beginning of the array. Vue will also automatically update the view when the user clicks the button.

4. splice method

The splice method can be used to add or delete elements in an array, and you can specify the positions to add and delete. Its syntax is as follows:

array.splice(index, howmany, item1, ....., itemX)

Among them, the index parameter indicates the starting position of adding or deleting elements, the howmany parameter indicates the number of elements to be deleted, and item1 to itemX are the elements to be added. When using the splice method, Vue will automatically update the view so that the user can see the modified array.

For example, we have the following Vue component:

<template>
  <div>
    <ul>
      <li v-for="item in items">{{ item }}</li>
    </ul>
    <button @click="addItem">添加</button>
    <button @click="delItem">删除</button>
  </div>
</template>

<script>
export default {
  data() {
    return {
      items: ["苹果", "西瓜", "香蕉"]
    };
  },
  methods: {
    addItem() {
      this.items.splice(1, 0, "橙子");
    },
    delItem() {
      this.items.splice(1, 1);
    }
  }
};
</script>

In this component, we use the splice method to add an "orange" at position 1 and delete an element at position 1. When the user clicks the button, Vue will automatically update the view to display the modified results.

Summary

Vue’s array modification functions include push, pop, shift and splice, etc. They can easily add, delete or change elements in the array, and Vue will automatically update the view, allowing The user sees the modified results. In actual development, we can flexibly apply these functions according to actual needs to improve development efficiency.

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