Ngfor with index

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NgFor is used as a structural directive that renders each element for the given collection each element can be displayed on the page. In this article, we will learn how to store the index value of ngFor in an attribute so I can utilize it. Step 2: After creating your project folder i. Example 1: In this example, we will use an index as i. Here, the Index is an attribute in ngFor which tells the sequence of the object retrieved. Here, the index is an attribute in ngFor which tells the sequence of the object retrieved.

Ngfor with index

Angular makes use of HTML for templates associated with components which eventually represent the views of your front-end application. A component controls a part of your application user interface and the associated template is what gets rendered in that part of the UI. The array must be present in the associated component. Here is how:. We use the ngFor directive to iterate over the array of movies and display the title of each movie. After the let keyword, we add a variable, which can be any valid variable name, that will be used to reference and access each element of the array and after the of keyword, we add the array of data which must be present in the component. Angular provides the reserved index keyword inside the ngFor expression which can be used as follows:. Inside the ngFor expression, we defined another variable called i which gets assigned the index keyword which simply contains the current index of each element in each iteration. And we used interpolation to display the value of the i and movie. Angular also provides the reserved first and last keywords for getting the first and last items in the array. Angular provides the trackBy feature which allows you to track elements when they are added or removed from the array for performance reasons. We can simply identify each element in a unique way using its id.

Here is how:.

In this post we are going to go over the ngFor core directive, namely we are going to go over the following:. So let's get started diving into ngFor! Below you can also find a video version of this post if you prefer, and the running code of this post is available here. Note: If instead of ngIf you are looking for the for syntax, then check my other guide instead: Angular for: Complete Guide. The core directive ngFor allows us to build data presentation lists and tables in our HTML templates. Let's take for example the following data:. With ngFor we can print this data to the screen under the form of a data table, by generating HTML similar to this:.

We will discover, how we can use the ngFor directive to display multiple elements directly from a JavaScript array. Also, we will take a look at the utilities of the ngFor directive, like the index, or even and odd. When we got the basics, we will move on to some more advanced topics like change-detection and DOM manipulation to tweak the performance of our for-loop using trackBy. We can use this directive, if we want to display a dynamic list, for example, an array of elements on the screen. This array could look like this example data:. That array could be static and look like the array above or could be filled at runtime. So to create a list-element for each array element, we place the ngFor directive inside of the li tag.

Ngfor with index

Angular makes use of HTML for templates associated with components which eventually represent the views of your front-end application. A component controls a part of your application user interface and the associated template is what gets rendered in that part of the UI. The array must be present in the associated component. Here is how:.

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Suggest Changes. ActivatedRoute just left the chat. Let's take for example the following data: With ngFor we can print this data to the screen under the form of a data table, by generating HTML similar to this: What is the syntax of ngFor? Write Angular like a pro. Improve Improve. This is the case if for example we query the data again from the backend. Also, when we pass to ngFor a new list, this does not mean that the whole list will be re-built, meaning all the DOM re-created. I hope you enjoyed the post, I invite you to have a look at the list below for other similar posts and resources on Angular. Google Developer Expert. Angular10 NgFor Directive.

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And we used interpolation to display the value of the i and movie. Cookies are used to analyze traffic and optimize experience. Turns out the QueryList is a class that is part of Angular and is itself an Iterable! React Bootstrap Tutorial. Also, when we pass to ngFor a new list, this does not mean that the whole list will be re-built, meaning all the DOM re-created. Angular templates just got the best upgrade in years: control flow blocks. Learn Angular the right way. Admission Experiences. Open In App. Create Improvement. Here is how:. Save Article. Why can this be important for performance? We can simply identify each element in a unique way using its id.