使用管道将数字转换为数组。

@Pipe({
  name: 'enumerate',
})
export class EnumeratePipe implements PipeTransform {
  transform(n: number): number[] {
    return [...Array(n)].map((_,i) => i);
  }
}

然后在模板中使用管道。

<p *ngFor="let i of 5 | enumerate">
   Index: {{ i }}
</p>

https://stackblitz.com/edit/angular-ivy-pkwvyw?file=src/app/app.component.html

下面是Angular的一些非常干净和简单的东西:

在.ts:

max = 10;    

. html:

<div *ngFor="let dummy of ','.repeat(max).split(','); index as ix">
   - {{ix + 1}}:
</div>

使用自定义结构指令索引:

根据Angular文档:

createEmbeddedView Instantiates an embedded view and inserts it into this container. abstract createEmbeddedView(templateRef: TemplateRef, context?: C, index?: number): EmbeddedViewRef. Param Type Description templateRef TemplateRef the HTML template that defines the view. context C optional. Default is undefined. index number the 0-based index at which to insert the new view into this container. If not specified, appends the new view as the last entry.

当angular通过调用createEmbeddedView创建模板时，它也可以传递将在ng-template中使用的上下文。

使用context可选参数，你可以在组件中使用它， 在模板中提取它，就像你使用*ngFor一样。

app.component.html:

<p *for="number; let i=index; let c=length; let f=first; let l=last; let e=even; let o=odd">
  item : {{i}} / {{c}}
  <b>
    {{f ? "First,": ""}}
    {{l? "Last,": ""}}
    {{e? "Even." : ""}}
    {{o? "Odd." : ""}}
  </b>
</p>

for.directive.ts:

import { Directive, Input, TemplateRef, ViewContainerRef } from '@angular/core';

class Context {
  constructor(public index: number, public length: number) { }
  get even(): boolean { return this.index % 2 === 0; }
  get odd(): boolean { return this.index % 2 === 1; }
  get first(): boolean { return this.index === 0; }
  get last(): boolean { return this.index === this.length - 1; }
}

@Directive({
  selector: '[for]'
})
export class ForDirective {
  constructor(private templateRef: TemplateRef<any>, private viewContainer: ViewContainerRef) { }

  @Input('for') set loop(num: number) {
    for (var i = 0; i < num; i++)
      this.viewContainer.createEmbeddedView(this.templateRef, new Context(i, num));
  }
}

我用Angular 5.2.6和TypeScript 2.6.2解决了这个问题:

class Range implements Iterable<number> {
    constructor(
        public readonly low: number,
        public readonly high: number,
        public readonly step: number = 1
    ) {
    }

    *[Symbol.iterator]() {
        for (let x = this.low; x <= this.high; x += this.step) {
            yield x;
        }
    }
}

function range(low: number, high: number) {
    return new Range(low, high);
}

它可以像这样在组件中使用:

@Component({
    template: `<div *ngFor="let i of r">{{ i }}</div>`
})
class RangeTestComponent {
    public r = range(10, 20);
}

为了简洁，故意省略错误检查和断言(例如，如果step为负会发生什么)。

<div *ngFor="let number of [].constructor(myCollection)">
    <div>
        Hello World
    </div>
</div>

这是一个在myCollection中重复相同次数的好方法。

如果myCollection是5,Hello World会重复5次。

NgFor还没有使用数字代替集合的方法， 目前，*ngFor只接受一个集合作为参数，但你可以通过以下方法做到这一点:

使用管

demo-number.pipe.ts:

import {Pipe, PipeTransform} from 'angular2/core';

@Pipe({name: 'demoNumber'})
export class DemoNumber implements PipeTransform {
  transform(value, args:string[]) : any {
    let res = [];
    for (let i = 0; i < value; i++) {
        res.push(i);
      }
      return res;
  }
}

对于新版本，你必须改变你的导入并删除args[]参数:

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({name: 'demoNumber'})
export class DemoNumber implements PipeTransform {
  transform(value) : any {
    let res = [];
    for (let i = 0; i < value; i++) {
        res.push(i);
      }
      return res;
  }
}

html:

<ul>
  <li>Method First Using PIPE</li>
  <li *ngFor='let key of 5 | demoNumber'>
    {{key}}
  </li>
</ul>

直接在HTML(视图)中使用数字数组

<ul>
  <li>Method Second</li>
  <li *ngFor='let key of  [1,2]'>
    {{key}}
  </li>
</ul>

使用Split方法

<ul>
  <li>Method Third</li>
  <li *ngFor='let loop2 of "0123".split("")'>{{loop2}}</li>
</ul>

使用在组件中创建新数组

<ul>
  <li>Method Fourth</li>
  <li *ngFor='let loop3 of counter(5) ;let i= index'>{{i}}</li>
</ul>

export class AppComponent {
  demoNumber = 5 ;
  
  counter = Array;
  
  numberReturn(length){
    return new Array(length);
  }
}

#演示工作