what is ngFor directive in Angular? How to use ngFor directive in Angular?

 ngFor is a structural directive in Angular that allows you to iterate over a collection, such as an array or object, and generate HTML elements for each item in the collection.

The ngFor directive is often used in combination with the *ngFor syntax, which is a shorthand way of declaring the directive in an HTML template.

Here is an example of using ngFor to iterate over an array of strings and display each string in a list:

html
<ul>
  <li *ngFor="let item of items">{{ item }}</li>
</ul>

In the above example, items is an array of strings defined in the component class. The *ngFor directive is used to iterate over the items array and generate an <li> element for each string in the array.

You can also use ngFor with objects by using the keyvalue pipe to iterate over the key-value pairs in the object. For example:

html
<div *ngFor="let item of myObject | keyvalue">
  Key: {{ item.key }}, Value: {{ item.value }}
</div>

In the above example, myObject is an object defined in the component class, and the keyvalue pipe is used with ngFor to iterate over the key-value pairs in the object and display them in the template.