Plot date and time

2012 3 29
1 个回答
更新时间：2014 8 12
2 次查看（30 天）

1 个投票

I have date and time values that I'd like to use for my XTick values. The data is in an array that has date, time and price. I would like to plot my price across multiple days and each time interval, 5 minute intervals. How can I set this up? Is it possible to set XTick to every 1.5 hours or every 18 ticks?
This is what I have right now but it doesn't accomplish what I want:
the array is 415x3 set like [date time price]
date = datenum(date,'mm/dd/yy');
time = datenum(time,'HH:MM');
count = length(time);
plot(price, count)
Thanks for your help!

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回答（1 个）

Thomas
Thomas 2012-3-29

0 个投票

If you have date and time as cell's in Vectors date in format cell{mm/dd/yy} time in format cell{HH:MM:SS}
1) concatenate them
dt_time=[date time];
2) convert cell to mat
dt_time_new=cell2mat(dt_time);
3) convert to datenum here
final_time=datenum(dt_time_new,'mm/dd/yyHH:MM:SS');
plot(final_time,price)
datetick('x','mm/dd','keepticks') % or which ever format you want

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Trader
Trader 2012-3-29
Is there a way to do this if date and time are already in serial format?
Thomas
Thomas 2012-3-29
Can you show an example of date time array
Trader
Trader 2012-3-30
I am using the import() function to pull data from a .csv file and then assigning the values to a structure "f" after converting the dates to serial values
import = importdata(full_path);
% the first column (starting from the second row) is the trading days in format mm/dd/yyyy.
idate = import.textdata(2:end,2);
itime = import.textdata(2:end,3);
f.date = datenum(idate,'mm/dd/yy');
f.time = datenum(itime,'HH:MM');
% Create OHLC matricies
f.price_close=import.data(:,4);
Thanks again for you help!
Geoff
Geoff 2012-3-30
That line f.time will not give you a sensible result. I tried this. You need to do:
f.time = mod(datenum(itime,'HH:MM'), 1);
Then you can use:
final_time = f.date + f.time;
Alternatively, you can do this (if you don't need to split date and time in the first place):
f.datetime = datenum( [idate ' ' itime], 'mm/dd/yy HH:MM');
Geoff
Geoff 2012-3-30
Oh, actually you probably can't do my last suggestion cos your strings are gonna be in a cell array. You could use cellfun, but given that you are asking how to apply Thomas' answer to your code which is nearly identical, maybe you should stay away from cellfun for now! =)
Trader
Trader 2012-4-3
Geoff - Could you give me your suggestion on how to use cellfun to accomplish this? I'm interested in learning.
KRUNAL
KRUNAL 2014-8-12
编辑：KRUNAL 2014-8-12
Thomas I tried using it. It says datenum failed for line 23
This is my code.
clc;
clear all;
orginf = '<filename>';
sheet = 'Sheet1';
for n =1:151
xlrange = ['C' num2str(n+1)];
a = xlsread (orginf,sheet,xlrange);
if a==1
range = ['E' num2str(n+1)];
range1 = ['F' num2str(n+1)];
range2 = ['S' num2str(n+1)];
[~,~,b] = xlsread(orginf,sheet,range);
c = xlsread(orginf,sheet,range1);
d = {datestr(c,'HH:MM:SS')};
dt_time = [b,d];
[~,~,mag] = xlsread(orginf,sheet,range2);
mag_new = double(cell2mat(mag));
dt_time_new=cell2mat(dt_time)
final_time=datenum(dt_time_new,'mm/dd/yyHH:MM:SS'); %line 23
plot(final_time,mag_new)
datetick('x','mm/dd','keepticks')
end
end
and my data in the various columns are as follows :
Stage Magnitude Date Time
1 -1 06/10/2012 17:56:50
1 -3 06/10/2012 17:59:33
2 -2 06/11/2012 8:52:45
2 -5 06/11/2012 8:52:46
3 -3 06/12/2012 9:11:37
3 -4 06/12/2012 9:55:56
3 -1 06/12/2013 9:57:46
4 -5 06/12/2013 10:47:49
4 -2 06/12/2013 10:48:08
4 -4 06/12/2013 10:50:35
5 -3 06/12/2013 7:47:43
5 -1 06/12/2013 8:15:30
5 -2 06/12/2013 8:16:04
I am trying to plot magnitude v/s date time. Please suggest me what is wrong with it ?

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Trader
Trader
2012-3-29

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KRUNAL
KRUNAL
2014-8-12

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