ngFor Directive

To understand ngFor lets create a new Angular project using angular CLI

Write the below contents in app.component.html file

<h2>List of colors</h2>
<ul *ngFor="let color of colors">
  <li>{{color}}</li>
</ul>
<h2>Displaying colors using index of ngFor</h2>
<div *ngFor="let color of colors; let i = index">
  <p>{{i+1}} - {{color}}</p>
</div>

Write the below contents into app.component.ts file

import { Component } from '@angular/core';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'ngForDemo';
  colors = ['Read','Yellow','Blue','Green'];
}

After running the code on server the output will look like below :

Example 2: Fetching data using Observables

app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { FormsModule } from '@angular/forms';
import { HttpClientModule } from '@angular/common/http';

import { AppComponent } from './app.component';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpClientModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

app.component.ts

import { Component, OnInit } from '@angular/core';
import { HttpClient } from '@angular/common/http';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit{
  title = 'DemoNgFor';
  names = ['Hello'];
  colors = ['Read', 'Yellow', 'Blue', 'Green'];
  ngOnInit(): void {
    this.getDataFromApi();
  }
  constructor(private http: HttpClient){}

  getDataFromApi(){
    this.http.get<[]>('/assets/data/listUsers.json').subscribe(
      (response) => {console.log('Response ' + response); this.names = response; },
      (error) => {console.log(error); },
      () => {console.log('Completed'); }
    );
  }
}

listUsers.json

[
  "Tyson",
  "Justin",
  "Martin"
]

app.component.html

<select>
    <option *ngFor="let name of names; let i = index" [value]="name">
        {{name}}
      </option>
</select>

Output :