如何解析 JSONArray 并在 Javascript 中转换答案

【问题标题】：How to parse a JSONArray and convert in Javascript如何解析 JSONArray 并在 Javascript 中转换
【发布时间】：2016-09-08 18:42:19
【问题描述】：

我有一个这种格式的 JSONArray：

[
{"COMPLIANCE_ID":"1/FIRST/US/191CC2/20160906/pW1WSpD/1","TOLERANCE":null,"WEIGHTED_ARR_LAST_SLP":"0.03801186624130076","SLIPPAGE_INTERVAL_VWAP_BPS":"10.2711","ROOT_ORDER_ID":"735422197553491","ENTERING_TRADER":"duffy_dma2","SECURITY_ID":"EOG.N","ARRIVAL_MID_PX":"93.6100","WEIGHTED_ARR_SLP":"0.12323190317127024","AVG_PX":"93.6586","ORDER_CCY":"USD","LEAVES_QTY":"0","WEIGHT":"0.02372627566400397","INITIATING_TRADER":null,"PARTICIPATION_RATE":"0E-12","LOCAL_REF_END_TIME":"2016-09-06 06:00:27.775","WEIGHTED_IVWAP_SLP":"0.2436949499725512","NOTIONAL_USD":"477940","LIST_ID":null,"SYM":"EOG","LIQ_CONSUMPTION":"15.21","URGENCY":null,"SIDE":"Sell Short","ALGO":"Hydra","EXECUTING_TRADER":"duffy_dma2","EXEC_QTY":"5103","CL_ORD_ID":"7245294057012908344","LOCAL_REF_START_TIME":"2016-09-06 05:59:57.844","SLIPPAGE_END_LAST_ARR_LAST_BPS":"1.6021","ORD_STATUS":"Filled","IVWAP_PX":"93.5625","LIMIT_PX":"93.6100","ORDER_ID":"735422197553491","VOLUME_LIMIT":"0E-12","SLIPPAGE_ARR_MID_BPS":"5.1939","ORDER_QTY":"5103","CLIENT_ACRONYM":"PEAKM","EXECUTION_STYLE":"2"},{"COMPLIANCE_ID":"1/FIRST/US/191CC2/20160906/pW1PUxP/1","TOLERANCE":null,"WEIGHTED_ARR_LAST_SLP":"-0.046488357264395964","SLIPPAGE_INTERVAL_VWAP_BPS":"0.1625","ROOT_ORDER_ID":"73855219760798","ENTERING_TRADER":"duffy_dma2","SECURITY_ID":"MCD.N","ARRIVAL_MID_PX":"118.0950","WEIGHTED_ARR_SLP":"-0.0041198933937856425","AVG_PX":"118.0923","ORDER_CCY":"USD","LEAVES_QTY":"0","WEIGHT":"0.01830250285999841","INITIATING_TRADER":null,"PARTICIPATION_RATE":"0E-12","LOCAL_REF_END_TIME":"2016-09-06 05:32:24.895","WEIGHTED_IVWAP_SLP":"0.002974156714749742","NOTIONAL_USD":"368684","LIST_ID":null,"SYM":"MCD","LIQ_CONSUMPTION":"62.82","URGENCY":null,"SIDE":"Sell","ALGO":"Hydra","EXECUTING_TRADER":"duffy_dma2","EXEC_QTY":"3122","CL_ORD_ID":"7244573979975932119","LOCAL_REF_START_TIME":"2016-09-06 05:32:19.697","SLIPPAGE_END_LAST_ARR_LAST_BPS":"-2.5400","ORD_STATUS":"Filled","IVWAP_PX":"118.0904","LIMIT_PX":"117.9900","ORDER_ID":"73855219760798","VOLUME_LIMIT":"0E-12","SLIPPAGE_ARR_MID_BPS":"-0.2251","ORDER_QTY":"3122","CLIENT_ACRONYM":"PEAKM","EXECUTION_STYLE":"4"}]

这里所有的整数如"93.6585" 等都显示为字符串。是否可以将整数/浮点数转换为它们的原始类型（即整数/浮点数）？背景信息：我在 Javascript 中使用这个 JSONArray，然后想对每一列进行排序，但是因为这些显示为字符串，所以排序不正确。

这就是我需要 javascript 中的 json 列的方式。那么，我应该在哪里为 ORDER QTY(say) 字段添加 parseInt 或 Number？

【问题讨论】：

提前知道哪些值需要转换？例如，您是否知道只有 LIQ_CONSUMPTION 和 WEIGHT 的值需要转换为数字。另一种方法是您将尝试转换所有看起来是数字的东西，其中可能包括 CL_ORD_ID 甚至 ORD_STATUS（假设恰好只包含一个数字）？
@Vld 是的，所有出现数字的东西都应该转换为数字。
你确定吗？甚至身份证？因为那些通常不应该。
是的，我需要。上面 JSONArray 中出现的所有数字都需要转换为数字。我如何在上面的 JS 中做到这一点？
请漂亮地打印您的第一个数组。您可以循环遍历每个数组元素中的值，如果值已定义并且不是空字符串 isNaN() 应该告诉您您是否没有处理数字并且 - - 生成数字：if (typeof value !== 'undefined' && value != '' && ! isNaN(value)){ value=- -value };。另见：isNaN examples.

标签： javascript arrays json parsing

【解决方案1】：

为了转换所有数值，这就足够了：

var data = [{"COMPLIANCE_ID":"1/FIRST/US/191CC2/20160906/pW1WSpD/1","TOLERANCE":null,"WEIGHTED_ARR_LAST_SLP":"0.03801186624130076","SLIPPAGE_INTERVAL_VWAP_BPS":"10.2711","ROOT_ORDER_ID":"735422197553491","ENTERING_TRADER":"duffy_dma2","SECURITY_ID":"EOG.N","ARRIVAL_MID_PX":"93.6100","WEIGHTED_ARR_SLP":"0.12323190317127024","AVG_PX":"93.6586","ORDER_CCY":"USD","LEAVES_QTY":"0","WEIGHT":"0.02372627566400397","INITIATING_TRADER":null,"PARTICIPATION_RATE":"0E-12","LOCAL_REF_END_TIME":"2016-09-06 06:00:27.775","WEIGHTED_IVWAP_SLP":"0.2436949499725512","NOTIONAL_USD":"477940","LIST_ID":null,"SYM":"EOG","LIQ_CONSUMPTION":"15.21","URGENCY":null,"SIDE":"Sell Short","ALGO":"Hydra","EXECUTING_TRADER":"duffy_dma2","EXEC_QTY":"5103","CL_ORD_ID":"7245294057012908344","LOCAL_REF_START_TIME":"2016-09-06 05:59:57.844","SLIPPAGE_END_LAST_ARR_LAST_BPS":"1.6021","ORD_STATUS":"Filled","IVWAP_PX":"93.5625","LIMIT_PX":"93.6100","ORDER_ID":"735422197553491","VOLUME_LIMIT":"0E-12","SLIPPAGE_ARR_MID_BPS":"5.1939","ORDER_QTY":"5103","CLIENT_ACRONYM":"PEAKM","EXECUTION_STYLE":"2"},{"COMPLIANCE_ID":"1/FIRST/US/191CC2/20160906/pW1PUxP/1","TOLERANCE":null,"WEIGHTED_ARR_LAST_SLP":"-0.046488357264395964","SLIPPAGE_INTERVAL_VWAP_BPS":"0.1625","ROOT_ORDER_ID":"73855219760798","ENTERING_TRADER":"duffy_dma2","SECURITY_ID":"MCD.N","ARRIVAL_MID_PX":"118.0950","WEIGHTED_ARR_SLP":"-0.0041198933937856425","AVG_PX":"118.0923","ORDER_CCY":"USD","LEAVES_QTY":"0","WEIGHT":"0.01830250285999841","INITIATING_TRADER":null,"PARTICIPATION_RATE":"0E-12","LOCAL_REF_END_TIME":"2016-09-06 05:32:24.895","WEIGHTED_IVWAP_SLP":"0.002974156714749742","NOTIONAL_USD":"368684","LIST_ID":null,"SYM":"MCD","LIQ_CONSUMPTION":"62.82","URGENCY":null,"SIDE":"Sell","ALGO":"Hydra","EXECUTING_TRADER":"duffy_dma2","EXEC_QTY":"3122","CL_ORD_ID":"7244573979975932119","LOCAL_REF_START_TIME":"2016-09-06 05:32:19.697","SLIPPAGE_END_LAST_ARR_LAST_BPS":"-2.5400","ORD_STATUS":"Filled","IVWAP_PX":"118.0904","LIMIT_PX":"117.9900","ORDER_ID":"73855219760798","VOLUME_LIMIT":"0E-12","SLIPPAGE_ARR_MID_BPS":"-0.2251","ORDER_QTY":"3122","CLIENT_ACRONYM":"PEAKM","EXECUTION_STYLE":"4"}]

function isNumeric(n) { 
	return !isNaN(parseFloat(n)) && isFinite(n);
}

var parsedData = data.map(function(obj) {
	return Object.keys(obj).reduce(function(memo, key) {
		var value = obj[key];
		memo[key] = isNumeric(value) ? Number(value) : value;
		
		return memo;
	}, {})
})

console.log(parsedData);

isNumeric() - 该实现取自here，因为它是一种确定数据是否为数字的可靠方法，包括检测负数和浮点等。

可以使用替代方法，但要注意误报或误报。

Array.map() 将遍历数组并转换每个对象

Object.keys() 从对象中提取所有键

Array.reduce() 最终将该数组转换为一个新对象，转换它遇到的任何看起来是数字的值。请注意在调用结束时传递的{} - reduce(func, {}) - 这很重要，因为它是用于归约函数的初始值。

【讨论】：

【解决方案2】：

您可以通过以下方式将字符串转换为整数和浮点数：

parseFloat("1231.123");
parseInt("12");
Number("123");
Number("123.12");

来源：

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseFloat https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt

【讨论】：

或使用Number("123")，它可以让您进行更好、更轻松的转换。
@Vld 对此一无所知。将其添加到我的原始帖子中。
或者只是简单地 +"123"
不要忘记在每次使用 parseFloat 或 parseInt 时添加基数。例如parseInt('123', 10).
@VincentTaing parseFloat 不采用基数。如果没有提供，parseInt 会并且可能会做出奇怪的假设。两者都进行解析而不是转换。这很奇怪，但值得考虑 - parseInt("1abc7") 会给你1，因为一旦它找到a，它就会停止解析，退出并给你到目前为止它提取的任何东西。因此，为什么我在很多情况下发现Number 更好，它会进行转换，这意味着如果你给它相同的字符串，这是一个无效的数字，你会得到NaN。

【解决方案3】：

尝试运行它

var data =[{"COMPLIANCE_ID":"1/FIRST/US/191CC2/20160906/pW1WSpD/1","TOLERANCE":null,"WEIGHTED_ARR_LAST_SLP":"0.03801186624130076","SLIPPAGE_INTERVAL_VWAP_BPS":"10.2711","ROOT_ORDER_ID":"735422197553491","ENTERING_TRADER":"duffy_dma2","SECURITY_ID":"EOG.N","ARRIVAL_MID_PX":"93.6100","WEIGHTED_ARR_SLP":"0.12323190317127024","AVG_PX":"93.6586","ORDER_CCY":"USD","LEAVES_QTY":"0","WEIGHT":"0.02372627566400397","INITIATING_TRADER":null,"PARTICIPATION_RATE":"0E-12","LOCAL_REF_END_TIME":"2016-09-06 06:00:27.775","WEIGHTED_IVWAP_SLP":"0.2436949499725512","NOTIONAL_USD":"477940","LIST_ID":null,"SYM":"EOG","LIQ_CONSUMPTION":"15.21","URGENCY":null,"SIDE":"Sell Short","ALGO":"Hydra","EXECUTING_TRADER":"duffy_dma2","EXEC_QTY":"5103","CL_ORD_ID":"7245294057012908344","LOCAL_REF_START_TIME":"2016-09-06 05:59:57.844","SLIPPAGE_END_LAST_ARR_LAST_BPS":"1.6021","ORD_STATUS":"Filled","IVWAP_PX":"93.5625","LIMIT_PX":"93.6100","ORDER_ID":"735422197553491","VOLUME_LIMIT":"0E-12","SLIPPAGE_ARR_MID_BPS":"5.1939","ORDER_QTY":"5103","CLIENT_ACRONYM":"PEAKM","EXECUTION_STYLE":"2"},{"COMPLIANCE_ID":"1/FIRST/US/191CC2/20160906/pW1PUxP/1","TOLERANCE":null,"WEIGHTED_ARR_LAST_SLP":"-0.046488357264395964","SLIPPAGE_INTERVAL_VWAP_BPS":"0.1625","ROOT_ORDER_ID":"73855219760798","ENTERING_TRADER":"duffy_dma2","SECURITY_ID":"MCD.N","ARRIVAL_MID_PX":"118.0950","WEIGHTED_ARR_SLP":"-0.0041198933937856425","AVG_PX":"118.0923","ORDER_CCY":"USD","LEAVES_QTY":"0","WEIGHT":"0.01830250285999841","INITIATING_TRADER":null,"PARTICIPATION_RATE":"0E-12","LOCAL_REF_END_TIME":"2016-09-06 05:32:24.895","WEIGHTED_IVWAP_SLP":"0.002974156714749742","NOTIONAL_USD":"368684","LIST_ID":null,"SYM":"MCD","LIQ_CONSUMPTION":"62.82","URGENCY":null,"SIDE":"Sell","ALGO":"Hydra","EXECUTING_TRADER":"duffy_dma2","EXEC_QTY":"3122","CL_ORD_ID":"7244573979975932119","LOCAL_REF_START_TIME":"2016-09-06 05:32:19.697","SLIPPAGE_END_LAST_ARR_LAST_BPS":"-2.5400","ORD_STATUS":"Filled","IVWAP_PX":"118.0904","LIMIT_PX":"117.9900","ORDER_ID":"73855219760798","VOLUME_LIMIT":"0E-12","SLIPPAGE_ARR_MID_BPS":"-0.2251","ORDER_QTY":"3122","CLIENT_ACRONYM":"PEAKM","EXECUTION_STYLE":"4"}];

function isInt(n){
  if (n === null) return;
  n = Number(n);
  return !isNaN(n) && n % 1 === 0;
}

function isFloat(n) {
  if (n === null) return;
  n = Number(n);
  return !isNaN(n) && n % 1 !== 0;
}

var result = data.map(function(currVal) {
  for (var i = 0, keys = Object.keys(currVal), len = keys.length; i < len; i++) {
    var key = keys[i];
    var item = currVal[key];
    isInt(item) && (currVal[key] = parseInt(item));
    isFloat(item) && (currVal[key] = parseFloat(item));  
}
  return currVal;
});

console.log(result);

【讨论】：

为什么还要有isInt 和isParse 函数来决定是使用parseInt 还是parseFloat？ 根据定义，当您调用parseX 时，您已经获得了数值。这意味着如果您拨打parseFloat(item)，这是您第三次从字符串中获取号码。有趣的是——使用parseInt 或parseFloat 都没有关系，因为JavaScript 不区分整数和浮点数。省去你自己的麻烦和代码，用Number(item)替换所有的代码。
@Vld 根据我提供的 javascript 代码，我仍然无法理解如何使用 Number(item)。