changing the x axis candle stick chart

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AA 2016-11-4

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https://ww2.mathworks.cn/matlabcentral/answers/310714-changing-the-x-axis-candle-stick-chart

评论： Nick Counts 2016-11-9

采纳的回答： Nick Counts

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drawing this candle stick chart gives me the following error

candle(col2,col3,col4,col1,'b',tt,'dd-MM-yyyy HH:mm:SS')

Error using candle (line 132) Function 'subsindex' is not defined for values of class 'cell'.

I just want the the x-axis of the candle stick chart to show the dates which i have saved in a datetime array.

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Answer 1

Nick Counts 2016-11-6

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编辑：Nick Counts 2016-11-6

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Sorry, it looks like I misunderstood your issue. Without seeing what your variables are (data types, sizes, etc) it's a little tricky to debug your code, but here is an example with two approaches that should help:

    % Load Sample Data
        load disney;
    % Build a vector of datenums for the x axis
        dateNumVector = floor(now)-20:floor(now)-10;
        dateNumVector = dateNumVector'; % Must be a column vector
    % Method 1: Using a datenum array:
        fh1 = figure;
    % candle plot with the x-axis datenum argument
        candle(  dis_HIGH(end-20:end-10), ...
                dis_LOW(end-20:end-10), ...
                dis_CLOSE(end-20:end-10),...
                dis_OPEN(end-20:end-10), ...
                'b', ...
                dateNumVector);
    % Method 2: Using datetime object array
        fh2 = figure;
    % build an example datetime object array:
        dateTimeArray = datetime(datestr(dateNumVector));
    % candle plot with x-ais date argument    
        candle(  dis_HIGH(end-20:end-10), ...
                dis_LOW(end-20:end-10), ...
                dis_CLOSE(end-20:end-10),...
                dis_OPEN(end-20:end-10), ...
                'b', ...
                dateTimeArray.Day);

Note that in your sample line of code, if class(tt) is datetime then you have to use the Day method to pass dates in the form candle is expecting.

Hopefully this will get you sorted out :)

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Nick Counts 2016-11-8

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Without seeing your code, this is tough. If you could post the code, or a small example that would really help us understand what's going on.

I don't think I understand the data type of your variable tt.

If it is a datetime then it is an object with specific methods.

From your last comment, it sounds like maybe you have a cell array of strings.

If that is the case, then you want to look at

doc datenum

datenum will take a cell array of strings as an input and convert it to a double that uses Matlab's convention for representing time.

    % Method 3: Convert a cell array of strings to dates
        fh3 = figure;
    % build an example cell array of strings:
        cellArrayOfStrings = {  
            '18-Sep-2014 16:33:00';
            '18-Sep-2014 17:26:00';
            '18-Sep-2014 18:22:00';
            '18-Sep-2014 19:14:00';
            '18-Sep-2014 20:11:00';
            '18-Sep-2014 21:04:00';
            '18-Sep-2014 21:56:00';
            '18-Sep-2014 22:48:00';
            '18-Sep-2014 23:40:00';
            '19-Sep-2014 00:33:00';
            '19-Sep-2014 01:25:00';
            '19-Sep-2014 02:18:00';
            '19-Sep-2014 03:10:00';
            '19-Sep-2014 04:02:00'};
    % build a set of example stock data (doubles)
        col1 = randi(100, 14, 1);
        col2 = randi(100, 14, 1);
        col3 = randi(100, 14, 1);
        col4 = randi(100, 14, 1);
    % candle plot with x-ais date argument from cell array of strings  
        candle(  col1, ...
                col2, ...
                col3, ...
                col4, ...
                'b', ...
                datenum(cellArrayOfStrings));

Hopefully that helps. If it doesn't, please try to post your code and we'll get it sorted.

Nick Counts 2016-11-9

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AA, I think it would be really helpful if we could see a sample of NewMATRIX2. Do you mean that the first column is minutes and the second column is the serial date (as in, the output of Matlab's datenum)?

And forgive me if this sounds condescending, as it is not my intention, but do you intend to use duration objects and datetime objects?

If you don't need the class methods, it may be much simpler (and clearer) to use good-old serial dates, which are just represented as doubles and are supported by virtually all of Matlab's plotting functions (including candle)

Unfortunately, I can't run your sample code without guessing at what NewMATRIX2, date_num, and numOnly are.

This is my new guess:

Based on your previous question regarding importing excel times, I suspect this all stems from trying to get a usable representation of a timestamp (I will use timestamp to mean date and time) that you can use as the x-axis variable in your candle plot and also to specify the labeling of the x-axis on your plot.

Please post an example of your input (whatever variables you are starting with). It would also be very helpful to include sample code that we can copy-paste and run. You can include a sample variable like:

    NewMATRIX2 = [736613, 60;
                  736614, 78;
                  736615, 42;
                  736616, 124;
                  736617, 256;
                  736618, 38]

We can get figure this out, we just need to know a little more :)

Nick Counts 2016-11-9

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This is an educated guess based on your other questions:

    clear
    inputArray = {
                    'Mon, Apr-25-16'  0.0763888888888889;
                     NaN                  NaN;
                    'Mon, Apr-25-16'  0.0763888888888889;
                    'Fri, Mar-25-16'  0.0347222222222222;
                    'Wed, Feb-24-16'  0.0347222222222222;
                    'Tue, Jan-26-16'  0.0347222222222222;
                    'Fri, Dec-25-15'  0.0347222222222222;
                    'Wed, Nov-25-15'  0.0347222222222222;
                    };
    % Get rid of nan
        rowsToRemove = isnan([inputArray{:,2}]');
        inputArray(rowsToRemove,:) = [];
    dateMatrix = datevec(inputArray(:,1),'ddd, mmm-dd-yy');
    % make the Matlab serial date
        timeStamp = datenum(dateMatrix);
    % Add the 'time' portion, which is a fraction of a day
        timeStamp = timeStamp + [inputArray{:,2}]' ;
    % build a set of example stock data (doubles)
        col1 = randi(100, 7, 1);
        col2 = randi(100, 7, 1);
        col3 = randi(100, 7, 1);
        col4 = randi(100, 7, 1);
    % candle plot with x-ais date argument from cell array of strings  
        candle(  col1, ...
                col2, ...
                col3, ...
                col4, ...
                'b', ...
                timeStamp, ...
                'dd/mm/yy');

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Answer 2

Nick Counts 2016-11-4

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编辑：Nick Counts 2016-11-4

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try dateaxis

    load disney;
    candle(dis_HIGH(end-20:end), ...
           dis_LOW(end-20:end), ...
           dis_CLOSE(end-20:end),...
           dis_OPEN(end-20:end), 'b');
    dateaxis;