V-if inside v-for - display list of items in two columns

What I would do is create a computed property dividing (or chunking) the items array into the appropriate number of columns.

Here's an example that uses a flexbox layout and one extra column element.

new Vue({
  el: 'main',
  data: {
    items: ['Item 1', 'Item 2', 'Item 3', 'Item 4', 'Item 5', 'Item 6', 'Item 7'],
    cols: 2
  },
  computed: {
    columns () {
      let columns = []
      let mid = Math.ceil(this.items.length / this.cols)
      for (let col = 0; col < this.cols; col++) {
        columns.push(this.items.slice(col * mid, col * mid + mid))
      }
      return columns
    }
  }
})

.container {
  display: flex;
  border: 1px solid;
}
.col {
  margin: 10px;
  border: 1px solid;
  flex-grow: 1;
  display: flex;
  flex-direction: column;
}
.item-container {
  border: 1px solid;
  padding: 5px;
  margin: 5px;
}

<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/vue.min.js"></script>
<main>
<p><label>Columns:<label> <input type="number" v-model="cols"></p>
<div class="container">
  <div class="col" v-for="column in columns">
    <div class="item-container" v-for="item in column">{{item}}</div>
  </div>
</div>
</main>

If you'd like a less verbose way of chunking the items array, see Split array into chunks

Its good to see someone who stumbled across the same problem as me. I had to position 6 items in each column. I sliced the API-response into the columns and printed them afterwards.

let allCategory = response.body.Categories.slice(); //clone
while (allCategory.length > 0) {
  let chunk = allCategory.splice(0,6);
  this.ColArray.push(chunk);
}  

ColArray is an array that then will contain arrays of the columns. It would look like this:

{
  ColArray: [
    Column1: [
      Item1,
      Item2,
      Item3,
    ],
    Column2: [
      ...
    ]
  ]
}

In Vue it will just be looped through, like this:

<div v-for="(col,colIndex) in ColArray" :key="'cate_col'+colIndex" class="col-md-2">
  <div v-for="(row,rowIndex ) in col"   :key="'cate_row'+colIndex + rowIndex" class="row">
    {{row}}
  </div>
</div>

Here is a sample fiddle :

https://jsfiddle.net/keysl183/50wL7mdz/775484/