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In the official website, there is an example of how to implement filtering which basically searches over all columns. I'm using the exact same code but I would like to only have it filter over the columns Position and Weight. Is there a way to exclude the other columns from the filtering or only include these two?

Edit: I see that my question is getting voted to close due to it being unclear. This is the code from the example:

<mat-form-field>
  <mat-label>Filter</mat-label>
  <input matInput (keyup)="applyFilter($event)" placeholder="Ex. ium">
</mat-form-field>

<table mat-table [dataSource]="dataSource" class="mat-elevation-z8">

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

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

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

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

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

import {Component} from '@angular/core';
import {MatTableDataSource} from '@angular/material/table';

export interface PeriodicElement {
  name: string;
  position: number;
  weight: number;
  symbol: string;
}

const ELEMENT_DATA: PeriodicElement[] = [
  {position: 1, name: 'Hydrogen', weight: 1.0079, symbol: 'H'},
  {position: 2, name: 'Helium', weight: 4.0026, symbol: 'He'},
  {position: 3, name: 'Lithium', weight: 6.941, symbol: 'Li'},
  {position: 4, name: 'Beryllium', weight: 9.0122, symbol: 'Be'},
  {position: 5, name: 'Boron', weight: 10.811, symbol: 'B'},
  {position: 6, name: 'Carbon', weight: 12.0107, symbol: 'C'},
  {position: 7, name: 'Nitrogen', weight: 14.0067, symbol: 'N'},
  {position: 8, name: 'Oxygen', weight: 15.9994, symbol: 'O'},
  {position: 9, name: 'Fluorine', weight: 18.9984, symbol: 'F'},
  {position: 10, name: 'Neon', weight: 20.1797, symbol: 'Ne'},
];

/**
 * @title Table with filtering
 */
@Component({
  selector: 'table-filtering-example',
  styleUrls: ['table-filtering-example.css'],
  templateUrl: 'table-filtering-example.html',
})
export class TableFilteringExample {
  displayedColumns: string[] = ['position', 'name', 'weight', 'symbol'];
  dataSource = new MatTableDataSource(ELEMENT_DATA);

  applyFilter(event: Event) {
    const filterValue = (event.target as HTMLInputElement).value;
    this.dataSource.filter = filterValue.trim().toLowerCase();
  }
}

/* Structure */
table {
  width: 100%;
}

.mat-form-field {
  font-size: 14px;
  width: 100%;
}

This searches over all columns but i would like it to only search over the aforementioned columns. Hope it is clear like this

I've followed this answer on SO but it is not working.

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1 Answer 1

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1

Add a custom filter function to override the default filter predicate.

    ngAfterViewInit() {
    this.dataSource.filterPredicate = function(data, filter: string): boolean {
      return (
        data.position.toString().includes(filter) ||
        data.weight.toString().includes(filter)
      );
    };
  }

Here numbers are converted to string to match 11 and 111 if user type 11

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8 Comments

Where am i supposed to add this exactly?
after this dataSource = new MatTableDataSource(ELEMENT_DATA);
this gives many errors like Duplicate declaration on this.dataSource.filterPredicate and non-arrow functions are forbidden(only-arrow-functions) on function crashing the export class and therefore the application
sorry forgot to mention about ngAfterViewInit
this works great, thanks. I'm wondering whether i could add column name as well. I've tried adding the following as an extra or clause data.name.toString().includes(filter) and data.weight.toString().indexOf(filter) !== -1 but both didn't work. Any suggestions?
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