title: react-table how create column headers and cells with array
body: <p>i'm using react-table in my project and i wonder how create headers dynamically with array.</p>
  
  <p>in my component i have: </p>
  
  <pre><code>const columns = [
    {Header: 'day', accessor: ''}, 
    {Header: 'day', accessor: ''}
  ]
  
  &lt;ReactTable
      className="-striped -highlight"
      data={this.props.items}
      columns={columns}
      defaultPageSize={20}/&gt;
  </code></pre>
  
  <p>and i have json data like that:</p>
  
  <pre><code>"items": [
      {
        "day": "01",
        "city": "A",
        "1": "",
        "2": "",
        "3": "",
        "4": null,
        "5": "",
        "6": 256,
        "7": 36.07,
        "8": 35.15,
        "9": "",
        "10": "",
        "11": 6.49,
        "12": 5.9,
        "13": "",
        "14": "",
        "15": 72.0,
        "16": 62.109375,
        "17": 266.78,
        "18": 83.59375,
        "19": 444.96
      },
      {
        "day": "02",
        "city": "B",
        "1": "",
        "2": "",
        "3": "",
        "4": null,
        "5": "",
        "6": 234,
        "7": 36.52,
        "8": 35.6,
        "9": "",
        "10": "",
        "11": 6.08,
        "12": 5.71,
        "13": "",
        "14": "",
        "15": 64.0,
        "16": 43.162393162393165,
        "17": 121.97,
        "18": 84.1880341880342,
        "19": 346.49
      },
      {
        "day": "03",
        "city": "B",
        "1": "",
        "2": "",
        "3": "",
        "4": null,
        "5": "",
        "6": 221,
        "7": 36.96,
        "8": 35.93,
        "9": "",
        "10": "",
        "11": 5.82,
        "12": 5.28,
        "13": "",
        "14": "",
        "15": 56.99999999999999,
        "16": 39.366515837104075,
        "17": 94.48,
        "18": 78.28054298642535,
        "19": 227.4
      },
     ]
  </code></pre>
  
  <p>so here is i want to make each item in items array will have column. and these columns headers will be their day property and cells will be values which in list 1, 2, 3, 5, 6. How can i do that ?</p>