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, ngfor with index.

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Ngfor with index

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:. This template will generate the HTML table that we showed just above. We can see in this example the most common syntax for using ngFor :. Note that the loop variable hero is only visible inside the loop, you would not be able to access it outside the ngFor section.

Many of the existing DOM elements will be reused and only some values inside them will be overwritten, and the decision is taken for each element in the list separately, ngfor with index.

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. Skip to content.

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.

Ngfor with index

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.

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Why can this be important for performance? Step 2: After creating your project folder i. Easy Normal Medium Hard Expert. How to use trackBy? Todd Motto Nov 23, We can see in this example the most common syntax for using ngFor :. Google Developer Expert. A newer version of this site just became available. Vote for difficulty :. We need to pass a function to trackBy , and the function takes a couple of arguments, which are an index and the current item:. See the bundle then add to cart and your discount is applied.

In this quick how-to tutorial we'll be learning about the ngFor directive in Angular and how to use it to display arrays of data in your Angular templates. For example, let's consider the following array of objects representing a set of products in a component:.

We need to pass a function to trackBy , and the function takes a couple of arguments, which are an index and the current item: This implementation would do the tracking based on the id property. Like Article Like. This will add a CSS class named first to the first element of the list, and a CSS class named last to the last element of the list:. Share your thoughts in the comments. The ngFor features are also covered in this video, have a look: What can we do with ngFor? 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. Add Other Experiences. In order to so, we have a couple of variables available for that: even and odd , that can be used in the following way together with ngClass : Let's have a look at the HTML generated by this template: As we can see, ngClass added the CSS classes to the right rows, as we would expect. Please refresh this page to activate it. Here, the index is an attribute in ngFor which tells the sequence of the object retrieved. Do you see what happened here? Below you can also find a video version of this post if you prefer, and the running code of this post is available here. Report issue Report. Improve Improve.