Shek Shek - 3 months ago 7
Javascript Question

How to parse a JSONArray and convert in Javascript

I have a JSONArray in this format:

[
{"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"}]


Here all the integers like
"93.6585"
etc. appear as strings. Is it possible to convert the integers/floats to their originate type (i.e., integer/float)?
Background information: I'm using this JSONArray in Javascript and then want to do sorting on each column, but because those appear as strings, sorting is not happening properly.

This is how I need the json columns in javascript. So, where do I add parseInt or Number for the field ORDER QTY(say)?

Vld Vld
Answer

In order to convert all numeric values this will suffuce:

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() - The implementation is taken from here because it is a robust way of figuring out if data is numeric or not including detecting negative numbers and floating points, among others.

Alternative one can be used but beware getting false positives or negatives.

Array.map() will iterate through the array and convert each object

Object.keys() extracts all the keys from the object

Array.reduce() finally transforms that array into a new object converting any value it encounters that looks numeric. Note the {} passed at the very end of the call - reduce(func, {}) - that is important, as it's the initial value used for the reduction function.