要在Angular 5的ng-bootstrap日期选择器中禁用特定日期，您可以使用ng-bootstrap的CustomDatepickerDayViewComponent来自定义日期选择器的外观和行为。以下是一个示例代码，演示如何禁用特定日期的数组：

1. 创建一个新的组件custom-datepicker-day-view.component.ts：

import { Component, Input } from '@angular/core';
import { NgbDatepickerDayView } from '@ng-bootstrap/ng-bootstrap';

@Component({
  selector: 'app-custom-datepicker-day-view',
  template: `
    
      

        {{ date.day }}
      
    
  `,
  styles: [
    `
    .disabled {
      background-color: #eee;
      color: #999;
    }
    `
  ]
})
export class CustomDatepickerDayViewComponent extends NgbDatepickerDayView {
  @Input() disabledDates: Date[];

  isDisabled(date: NgbDateStruct): boolean {
    const d = new Date(date.year, date.month - 1, date.day);
    return this.disabledDates.some(disabledDate => {
      return d.getTime() === disabledDate.getTime();
    });
  }
}

2. 在需要使用日期选择器的组件中，例如app.component.ts，添加以下代码：

import { Component } from '@angular/core';
import { NgbDateStruct } from '@ng-bootstrap/ng-bootstrap';

@Component({
  selector: 'app-root',
  template: `
    

      
ng-bootstrap Datepicker
      
    
  `,
  styles: [`
    .container {
      margin-top: 50px;
    }
  `]
})
export class AppComponent {
  customDayView = CustomDatepickerDayViewComponent;
  disabledDates: Date[] = [
    new Date(2021, 0, 1), // January 1, 2021
    new Date(2021, 0, 15) // January 15, 2021
  ];
}

3. 在app.module.ts中，将CustomDatepickerDayViewComponent添加到NgModule的declarations数组中：

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

import { AppComponent } from './app.component';
import { CustomDatepickerDayViewComponent } from './custom-datepicker-day-view.component';

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

这样，您就可以使用自定义日期选择器组件，并在disabledDates数组中指定要禁用的特定日期。