Help please!

[wilburforce83]

Hello everyone, I have just discovered this chart library, and I think it is exactly what I am looking for, but I just don't understand the data feed side of it. I have data streaming in an array of {epoch, open, high, low, close] It appends the latest candle and drops the earliest one off limiting it to 200 candles.

My question is to do with all the examples being from a .csv. I don't understand how I can replace this following section of code with my dynamic array:

    d3.csv("data.csv", function(error, csv) {
        var accessor = ohlc.accessor();

        feed = csv.map(function(d) {
            return {
                date: parseDate(d.Date),
                open: +d.Open,
                high: +d.High,
                low: +d.Low,
                close: +d.Close,
                volume: +d.Volume
            };
        }).sort(function(a, b) { return d3.ascending(accessor.d(a), accessor.d(b)); });

        // Start off an initial set of data
        redraw(feed.slice(0, 163));
    });

    function redraw(data) {
        var accessor = ohlc.accessor();

        x.domain(data.map(accessor.d));
        // Show only 150 points on the plot
        x.zoomable().domain([data.length-130, data.length]);

        // Update y scale min max, only on viewable zoomable.domain()
        y.domain(techan.scale.plot.ohlc(data.slice(data.length-130, data.length)).domain());
        yVolume.domain(techan.scale.plot.volume(data.slice(data.length-130, data.length)).domain());

        // Setup a transition for all that support
        svg
//          .transition() // Disable transition for now, each is only for transitions
            .each(function() {
                var selection = d3.select(this);
                selection.select('g.x.axis').call(xAxis);
                selection.select('g.y.axis').call(yAxis);
                selection.select("g.volume.axis").call(volumeAxis);

                selection.select("g.candlestick").datum(data).call(ohlc);
                selection.select("g.sma.ma-0").datum(sma0Calculator(data)).call(sma0);
                selection.select("g.sma.ma-1").datum(sma1Calculator(data)).call(sma1);
                selection.select("g.volume").datum(data).call(volume);

                svg.select("g.crosshair.ohlc").call(crosshair);
            });

        // Set next timer expiry
        setTimeout(function() {
            var newData;

            if(data.length < feed.length) {
                // Simulate a daily feed
                newData = feed.slice(0, data.length+1);
            }
            else {
                // Simulate intra day updates when no feed is left
                var last = data[data.length-1];
                // Last must be between high and low
                last.close = Math.round(((last.high - last.low)*Math.random())*10)/10+last.low;

                newData = data;
            }

            redraw(newData);
        }, (Math.random()*1000)+400); // Randomly pick an interval to update the chart
    }

    function move(coords) {
        coordsText.text(
                timeAnnotation.format()(coords.x) + ", " + ohlcAnnotation.format()(coords.y)
        );
    }

Any help or advice would be hugely appreciated!!

Thanks!

Will

[matricore]

Hi Will, I think you receive your data from a websocket connection. Pass your data on a global variable and call it from your settimeout function like below:

       ` var ndata = maindata.map(function(d) {

              darray = d.split(",");
                if (inter == 1) {
                    timestring = yyyy+"-"+(mm+1)+"-"+dd+"T" + darray[4];
                }
                else if (inter == 5 || inter == 15 || inter == 30 || inter == 60 || inter == 242) {
                        //1.2397,1.2429,1.2397,1.2426,3/28/2018 5:00:00 AM
                        var dateside = darray[4].split("T");

                        var datesidestring = dateside[0].split("/");
                        timestring = datesidestring[2]+"-"+datesidestring[0]+"-"+datesidestring[1]+"T" + dateside[1];

                }       
                else 
                {
                        // 1/2/2017
                        var ds = darray[4];
                        var datestrings = ds.split("/");
                        var newds = datestrings[2]+"-"+datestrings[0]+"-"+datestrings[1];
                        timestring = newds + "T12:00:00";
                        //console.log(timestring);
                }

              return {
                  date: parseDate(timestring),
                  open: +darray[0],
                  high: +darray[2],
                  low: +darray[3],
                  close: +darray[1],
                  volume: +darray[3]
              };

    }).sort(function(a, b) { return d3.ascending(accessor.d(a), accessor.d(b)); }); `

Tezcan

[wilburforce83]

@matricore Thank you so much for the quick response. I'll have a look and try this out.

Would you mind helping me out if I get stuck? I'm quite new to js so there are a few things I don't fully understand yet.

Thanks again!

[wilburforce83]

@matricore Okay, so I spent longer than I feel I should admit trying to get this work last night. I am missing something really simple, but I just can't get my head around it. I'm going to try and share as much info as possible in the hope that you might see the problem straight away!!

I have made a real mess of it think!!

So, you are correct, I am collecting the data from a websocket, I've created a paste of my whole page script, which includes the data acquisition for the array, just to put it all in one place, it is normally in a separate js file.

Please don't feel like you have to help me, but if you could possibly take a look at my code and maybe guide me on how to get it working, I be hugely appreciative. I am so keen to learn, but I am really struggling with this!

https://basilisk-design.co.uk/pastebin/paste.php?id=18

thank you so much in advance!!

Will

[GreatGranPa]

I think the easiest way would be to translate your input into the format that Techan usually uses. ie date ohlc. Don't be afraid to use the good old Print F Debugger... only when you are 100% sure that your input is of the same format feed it into techan. Best, U-------- Ursprüngliche Nachricht --------Betreff: Re: [andredumas/techan.js] Help please! (#239)Von: Will An: "andredumas/techan.js" Cc: Subscribed @matricore Okay, so I spent longer than I feel I should admit trying to get this work last night. I am missing something really simple, but I just can't get my head around it. I'm going to try and share as much info as possible in the hope that you might see the problem straight away!! I have made a real mess of it think!! So, you are correct, I am collecting the data from a websocket, I've created a paste of my whole page script, which includes the data acquisition for the array, just to put it all in one place, it is normally in a separate js file. Please don't feel like you have to help me, but if you could possibly take a look at my code and maybe guide me on how to get it working, I be hugely appreciative. I am so keen to learn, but I am really struggling with this! https://basilisk-design.co.uk/pastebin/paste.php?id=18 thank you so much in advance!! Will

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[wilburforce83]

@GreatGranPa thank you for your quick response!

I'll be honest, I think I am out of my depth at the moment! I am looking at using the chart within a larger project, and I am just learning JS in the process. I think what I am going to do is work on the rest of the project (which I am learning a lot while doing) and come back to the charting once I have more experience under my belt!!

Thanks guys!