Ng2-google-charts and changing amount of columns

Hello,
I installed ng2-google-charts.

I have In html

<google-chart [data]="pieChartData"></google-chart>

and in ts

public pieChartData: any = {
    chartType: 'PieChart',
    dataTable: [
      ['tic', 'tac'],
      ['a', 1],
      ['a', 1],
      ['a', 1],
      ['a', 1],
      ['a', 1]
    ],
    options: {
      //title: '',
      legend: 'none',
      width: 100,
      height: 100,
      backgroundColor: 'transparent',
      pieStartAngle: 0,
      is3D: false,
      pieHole: 0,
      sliceVisibilityThreshold: 0,
      pieSliceText: 'label',
      slices: {
        0: { offset: 0.0, color: 'DarkGreen' },//transparent macht unsictbar
        1: { offset: 0.0, color: 'DarkGreen' },
        2: { offset: 0.0, color: 'DarkGreen' },
        3: { offset: 0.0, color: 'transparent' },
        4: { offset: 0.0, color: 'transparent' },
      }
    }
  }

This works and render a pie, with 5 equal sized pie slices. 3 are darkgreen, 2 are something like semihidden. Looks good and I like it. On the demo page there is a example where the size of the pie silces (colums, are changing) but no the amount of columns.

Here I am struggling with my poor javascript knowledge.

I want equal sized pie slices, but with a @Input changing the amount of pie slices. For example Input = 3 then, 3 slices with 1/3 1/3 1/3 size.

Second an @Input with maybe 2, that makes the first 2 silces green, the rest transparent.

I played around with the example code from demopage

public changeData():void {
    // forces a reference update (otherwise angular won't detect the change
    this.columnChartData = Object.create(this.columnChartData);
    for (let i = 1; i < 7; i++) {
      this.columnChartData.dataTable[i][1] = Math.round(
        Math.random() * 1000);
      this.columnChartData.dataTable[i][2] = Math.round(
        Math.random() * 1000);
    }
  }

but I didn’t found a working way, changeing the columns (in his example code 7).

Thanks in advance and best regards, anna-liebt.