访问数组对象的子对象时未定义

Question

我已经完成了许多API调用，然后访问了他们的孩子，但是由于某些原因，我无法理解为什么这次我变得未定义。

当我做类似

的操作时

if (!this.props.newsLoading) {
            console.log(this.props.news["Data"]) //Line: 35
            console.log(this.props.news["Data"][0]) //Line: 36
        }

console.log(this.props.news["Data"])在控制台中显示如下

(50) [{…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}]


0: {id: "436511", guid: "https://www.coinspeaker.com/?p=58225", published_on: 1538583679, imageurl: "https://images.cryptocompare.com/news/coinspeaker/8kMa6p_wh01.jpeg", title: "Swell 2018: TransferGo Claims to Have Reduced Payments Cost by 90% Using Ripple Blockchain", …}
1: {id: "435701", guid: "https://bitcoinmagazine.com/articles/bitcoin-core-0170-released-heres-whats-new/#1538573301", published_on: 1538573301, imageurl: "https://images.cryptocompare.com/news/bitcoinmagazine/9GQ8h3mEd80.jpeg", title: "Bitcoin Core 0.17.0 Is Released: Here’s What’s New", …}
2: {id: "435621", guid: "https://www.cryptoglobe.com/latest/2018/10/shapesh…rhees-hits-back-at-deceptive-wall-street-journal/", published_on: 1538572500, imageurl: "https://images.cryptocompare.com/news/cryptoglobe/9m8933jy2gA.png", title: "ShapeShift, Voorhees Hits Back at “Deceptive” Wall Street Journal", …}
3: {id: "435609", guid: "https://cointelegraph.com/news/ibm-awarded-patent-for-secure-system-based-on-blockchain", published_on: 1538572200, imageurl: "https://images.cryptocompare.com/news/cointelegraph/d203500a88w.jpeg", title: "IBM Awarded Patent for Secure System Based on Blockchain", …}
4: {id: "435576", guid: "https://www.financemagnates.com/?p=242353", published_on: 1538571946, imageurl: "https://images.cryptocompare.com/news/financemagnates/8BxOkES8009.jpeg", title: "Israel Securities Authority Now Using Blockchain Technology", …}

但是当我执行类似console.log(this.props.news["Data"][0])的操作时，它正在控制台中记录未定义的内容。

问题：我在这里可能做错了什么？

注意：我不确定为什么人们会对此表示反对，但是如果他们也能说出同样的理由以便我改善问题，我将不胜感激

编辑：：由于某种原因，它先前无法运行，但现在已经开始运行。

Answer 1

尝试一下：

if (!this.props.newsLoading) {
            console.log(this.props.news["Data"]) //Line: 35
            console.log((this.props.news["Data"])[0]) //Line: 36
        }

代码的问题是，当您编写arr["data"][0]时，它意味着您具有二维数组数据，即arr[dim1][dim2]，但是在您的情况下，您只有一个维数组。因此，要从一维数组中获取数据，您需要用()包围变量，以将其视为一维数组。希望我足够清楚！如果您仍有任何疑问，请在下面发表评论。干杯！