how to define index in angular material table

Question

how should I define an index variable when angular material table is used as ngFor is not used in this table.

I did search for it in the documentation but index is not mentioned any where in it.

  <mat-table #table [dataSource]="dataSource">

    <!--- Note that these columns can be defined in any order.
          The actual rendered columns are set as a property on the row definition" -->

    <!-- Position Column -->
    <ng-container matColumnDef="position">
      <mat-header-cell *matHeaderCellDef> No. </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.position}} </mat-cell>
    </ng-container>

    <!-- Name Column -->
    <ng-container matColumnDef="name">
      <mat-header-cell *matHeaderCellDef> Name </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.name}} </mat-cell>
    </ng-container>

    <!-- Weight Column -->
    <ng-container matColumnDef="weight">
      <mat-header-cell *matHeaderCellDef> Weight </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.weight}} </mat-cell>
    </ng-container>

    <!-- Symbol Column -->
    <ng-container matColumnDef="symbol">
      <mat-header-cell *matHeaderCellDef> Symbol </mat-header-cell>
      <mat-cell *matCellDef="let element"> {{element.symbol}} </mat-cell>
    </ng-container>

    <mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
    <mat-row *matRowDef="let row; columns: displayedColumns;"></mat-row>
  </mat-table>
</div>

where and how do i define an index variable for the array that I used in this table, so that I can bind the index value in my table itself.

Can you handle the index value and set it when you fetch the data from the API? — Igor Dimchevski, Apr 04 '18 at 10:18

score 179 · Accepted Answer · edited Dec 02 '20 at 07:59

179

Can you add index to let element; let i = index;" as you'd do with *ngFor?

<mat-row *matRowDef="let row; columns: displayedColumns; let i = index"></mat-row>

Or like so:

<ng-container matColumnDef="index">
  <mat-header-cell *matHeaderCellDef> Index </mat-header-cell>
  <mat-cell *matCellDef="let element; let i = index;">{{i}}</mat-cell>
</ng-container>

Working Example: https://stackblitz.com/edit/angular-acdxje?file=app/table-basic-example.html

edited Dec 02 '20 at 07:59

Supun Wijerathne

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answered Apr 04 '18 at 10:22

Roberto Zvjerković

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Works! But I'd love to know where this came from....how did you know there's a variable index available to be consumed? Can someone explain this further please? – Ramiro G.M. Nov 21 '19 at 02:40
4

Take care that it will repeat per page if you enabled pagination – Eslam Sameh Ahmed May 25 '20 at 16:27
3

if you have pagination you can calculate row index like `{{this.paginator.pageIndex * this.paginator.pageSize + i}}` – Kasun Jan 12 '21 at 00:32
`let i=dataIndex` this is working for me. – Santosh Jan 21 '21 at 13:21
As mentioned in a comment above, please remove "this" keyword and try as {{paginator.pageIndex * paginator.pageSize + i}} and will work.! – Mohamed Musthaque Jun 09 '21 at 04:25

score 130 · Answer 2 · edited Feb 05 '19 at 08:42

130

For anyone who has set the multiTemplateDataRows property of mat-table to true, you can't use index. Instead you have use either dataIndex or renderIndex.

<mat-cell *matCellDef="let row; let i = dataIndex;">{{i}}</mat-cell>

See https://github.com/angular/material2/issues/12793

edited Feb 05 '19 at 08:42

Frederik Struck-Schøning

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answered Nov 28 '18 at 18:01

adam0101

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Take care that it will repeat per page if you enabled pagination – Eslam Sameh Ahmed May 25 '20 at 16:28

score 12 · Answer 3 · answered Jun 29 '19 at 21:39

For those who are facing problem with keeping the right index when using pagination which table has more than 1 page. It can be especially important when you have editable element, thus you're using a routerLink to add/edit/delete selected elements.

<ng-container matColumnDef="title">
 <mat-header-cell *matHeaderCellDef mat-sort-header>Title</mat-header-cell>
 <mat-cell *matCellDef="let book; let i = index;" fxLayoutAlign.lt-md="center center">
  <button mat-button [routerLink]="[i + (paginator.pageIndex * paginator.pageSize)]" routerLinkActive="active"</button>
 </mat-cell>
</ng-container>

As well as

<mat-paginator #paginator [pageSize]="5" [pageSizeOptions]="[5, 10, 25, 100]"></mat-paginator>

In essence, i + (paginator.pageIndex * paginator.pageSize) is the solution, but it counts from 0. If you'd like to index from 1, simply make it (i+1) + (paginator.pageIndex * paginator.pageSize). Worth to note is that you really need the #paginator and [pageSize]="VALUE".

`{{ (index + 1) + (paginator.pageIndex * paginator.pageSize) }}` works best for paginated data table. thanks. — Aamer Shahzad, Feb 27 '20 at 12:22
`Worth to note is that you really need the #paginator and [pageSize]="VALUE".` This is the real key. — Saurabh Tiwari, Dec 26 '20 at 06:14

score 8 · Answer 4 · answered Oct 10 '19 at 09:31

8

If someone using <mat-paginator ../>, then index can be interpreted as below

<mat-cell *matCellDef="let element; index as i"> {{paginator.pageSize * paginator.pageIndex + i + 1}}</mat-cell>

answered Oct 10 '19 at 09:31

Ram

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ElasticCode · Answer 5 · 2019-04-05T21:41:58.037

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From Angular 5 you can alias index to local variable i using index as i

<ng-container matColumnDef="rowIndex">
  <mat-header-cell *matHeaderCellDef> Index </mat-header-cell>
  <mat-cell *matCellDef="let element;index as i;"> {{ i }} </mat-cell>
</ng-container>

edited Apr 05 '19 at 21:41

answered Apr 05 '19 at 15:57

ElasticCode

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score 3 · Answer 6 · answered Jun 09 '21 at 04:22

If you are using pagination in your mat-table,

<ng-container matColumnDef="index">
   <mat-header-cell *matHeaderCellDef> Index </mat-header-cell>
   <mat-cell *matCellDef="let element; index as i">
        {{tableOnePaginator.pageSize * tableOnePaginator.pageIndex + i + 1}}</mat-cell>
</ng-container>

In here, this tableOnePaginator is need to define in your ts component before using it. And make sure you have set that to your dataSource as follows.

this.dataSource.paginator = this.tableOnePaginator;

score 2 · Answer 7 · answered Dec 31 '21 at 13:02

If you are using paginator and you want to place index with every page change then go with this below code; In .HTML file:-

<ng-container matColumnDef="Position">
   <th mat-header-cell *matHeaderCellDef> # </th>
   <td mat-cell *matCellDef="let element; let i= index"> {{i + 1 +
     (thirdPaginator.pageIndex*thirdPaginator.pageSize) }}</td>
</ng-container>

ErDeep · Answer 8 · 2023-04-18T11:19:34.163

1

Can you add index to let element; let i = index;" as you'd do with *ngFor?

<mat-row *matRowDef="let row; columns: displayedColumns; let i = index"></mat-row>

Also Add index column.

<ng-container matColumnDef="index">
  <mat-header-cell *matHeaderCellDef> Index </mat-header-cell>
  <mat-cell *matCellDef="let element; let i = index;">{{i + 1}}</mat-cell>
</ng-container>

edited Apr 18 '23 at 11:19

answered Apr 18 '23 at 11:12

ErDeep

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Harith Dilshan · Answer 9 · 2021-01-02T10:06:17.177

0

If you are use paginator try this:

<ng-container matColumnDef="position">
  <th mat-header-cell *matHeaderCellDef> Position </th>
  <td mat-cell *matCellDef="let element; let i = index"> {{(i+1) + (paginator.pageIndex*paginator.pageSize)}} </td>
</ng-container>

this working perfectly for Angular version 8.you must use #paginator and [pageSize]="VALUE"

edited Jan 02 '21 at 10:06

answered Jan 02 '21 at 10:03

Harith Dilshan

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score 0 · Answer 10 · answered May 28 '21 at 02:31

<td mat-cell *matCellDef="let row; let indx = dataIndex">

When using the multiTemplateDataRows directive to support multiple rows for each data object, the context of *matRowDef is the same except that the index value is replaced by dataIndex and renderIndex.

score 0 · Answer 11 · answered Oct 06 '22 at 03:22

0

<ng-container matColumnDef="Index">
   <th mat-header-cell *matHeaderCellDef> # </th>
   <td mat-cell *matCellDef="let element; index as i;">
      {{_paginator.pageSize * _paginator.pageIndex + i + 1}}    
   </td>
</ng-container>

Heading

answered Oct 06 '22 at 03:22

Tortu

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score 0 · Answer 12 · answered Jul 21 '23 at 12:41

In Angular 14, unique declaration that worked in my case is:

<td mat-cell *matCellDef="let row; let i = dataIndex">

In other parts of my app, index as i also works, but not always. I heard that using let i = index is written in old versions of Angular

how to define index in angular material table

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