I have 2 objects with data and I need to restruct the rendering in html.
This is what I get:

but this is what I need to obtain:

Black box is the *ngFor of articles object, respectively red one is *ngFor of adsContainer object
<div *ngFor="let article of articles; let i = index;">
<mat-card class="card">
<div>
<a class="title">
{{article.title}}
</a>
<a>
<p>{{article.content}}</p>
</a>
</div>
</mat-card>
<div class="container" *ngIf="(i % 7) === 6">
<div *ngFor="let data of adsContainer">
<div>
<h1>{{data.value}}</h1>
</div>
</div>
</div>
</div>
public adsContainer: any = [
{ id: '1', value: 'text value here' },
{ id: '2', value: 'text value here' },
{ id: '3', value: 'text value here' }
]
public articles: any = [
{ id: '1', title: 'title value here', content: 'content here' },
{ id: '2', title: 'title value here', content: 'content here' },
{ id: '3', title: 'title value here', content: 'content here' },
........
{ id: '20', title: 'title value here', content: 'content here' },
]
Try to use directly the array , also when you call adsContainer[(parseInt(i / 6)-1)% adsContainer.length, it will always restart the index:
<div *ngFor="let article of articles; let i = index;">
<mat-card class="card">
<div>
<a class="title">
{{article.title}}
</a>
<a>
<p>{{article.content}}</p>
</a>
</div>
</mat-card>
<div class="container" *ngIf="(i % 7) === 6">
<div>
<div>
<h1>{{adsContainer[(parseInt(i / 6)-1)%adsContainer.length].value}}</h1>
</div>
</div>
</div>
</div>
Your issue is that you add your ads containers in a loop
<div class="container" *ngIf="(i % 7) === 6">
<!-- this loop here -->
<div *ngFor="let data of adsContainer">
<div>
<h1>{{data.value}}</h1>
</div>
</div>
</div>
what you want is to add only one ad container at a time, in order to do that, you have to rmove the loop
In order to have the three ads show, you'll have to do some math to get the ad index from the article index
something like this :
<div class="container" *ngIf="(i % 7) === 6">
<div>
<h1>{{adsContainer[mathFloor(i / 7)].value}}</h1>
</div>
</div>
note that Math is not available in angular templates, you'll have to redefine floor as a component method
function mathFloor(val) {return Math.floor(val)}