pltoting a variable with dates on horizontial axis

Hello,

I am importing a data from excel by clicking on excel file and than click import.

the first column in my data is date, that is year , quarter. I want to create a plot of the variables. that i have done but in the figure i want to have date on the horizontal axis. I am having trouble in having date on the horizontal axis.

and i want to shade some of the periods in my plot. like from 1948 to 1950.

Please help me how i can do that.

[jonas]

Please upload the file

[Stephen23]

Muhammad Ramzan's "Answer" moved here:

I want to get the picture like this. Please let me now who i can do this. thanks

Answer 1

[jonas]

Here is something you can work from. I used a trick with the stairs and area functions to make the shaded bars. It may have been a bit overkill to use datetime in this case, but I could not resist. You can skip the first part if you'd prefer to use fraction years.

% load data
data=xlsread('MacroData.xlsx');
t=data(:,1);
y=data(:,7)
% Convert to datetime
year = floor(t);
fyear = years(mod(t,1));
ts=datetime(year,1,1)+fyear;

%Plot data
figure
hold on
h=plot(ts,y)

% fancy some shading? write list of [start time1; end time1; start time2; end time2...] and so on:
t2=[11 1948;10 1949;7 1953;5 1954;6 1957;4 1958;4 1960;2 1961;12 1969;11 1970;11 1973;3 1975;1 1980;7 1980;7 1981;11 1982;7 1990;3 1991;3 2001;11 2001;12 2007;6 2009]
t2=datetime(0,t2(:,1),1)+years(t2(:,2))
y2=zeros(1,length(t2))
y2(1:2:end)=1e6

% Fix shading
[xs,ys]=stairs(t2,y2)
ha=area(xs,ys,'facecolor',[0 0 0],'facealpha',.5,'edgecolor','none')
ylim([min(y) max(y)])

EDIT: Fixed an error found by Peter Perkins

[Stephen23]

Muhammad Ramzan's many "Answers" moved here and formatted correctly:

thanks a lot

mydata = xlsread('MacroData.xlsx');
TIME = mydata(:,1);
y = mydata(:,2);
figure(3)
plot(TIME,y)
myrecessions = [1950, 1952; 1980, 1983];
recessionplot('recessions', myrecessions);

I have made this code

but when i am plotting the series y i get this plot (image.png)

and when i try to run the last two commands I get teh grpahs with shaded are but the shaded area do not start with the horizontal axis. can you please let me know how to fix that Please.

getting this error message

Undefined function or variable 'timetable'.

and I have to shade the area according to the following table. the first number is the starting year and quarter and second number is the year and quarter.

Start Period   End Period
November 1948(IV)  October 1949 (IV)
July 1953(II)  May 1954 (II)
August 1957(III)  April 1958 (II)
April 1960(II)  February 1961 (I)
December 1969(IV)  November 1970 (IV)
November 1973(IV)  March 1975 (I)
January 1980(I)  July 1980 (III)
July 1981(III)  November 1982 (IV)
July 1990(III)  March 1991(I)
March 2001(I)  November 2001 (IV)
December 2007 (IV)  June 2009 (II)

[Muhammad Ramzan]

Hello @Stephen Cobeldick. thanks

@ jonas thanks for your help and answer.

mydata = xlsread('MacroData.xlsx');
TIME = mydata(:,1);
y = mydata(:,2);
figure(3)
plot(TIME,y)
myrecessions = [1950, 1952; 1980, 1983];
recessionplot('recessions', myrecessions);

can you please let me know how I can adjust/add the time from

[November 1948 , October 1949 ; July 1953,  May 1954 ; August 1957,April 1958 ;April 1960 , February 1961 ;December 1969, November 1970 ; November 1973, March 1975 ; January 1980, July 1980 ; July 1981 ,November 1982 ;July 1990 ,March 1991 ; March 2001 ,November 2001 ; 
December 2007 , June 2009 ]

in this command

myrecessions = [1950, 1952; 1980, 1983];

[jonas]

Oh, didnt know there was such a function as recession plot. On my phone atm but will have a look in a few hours.

[Muhammad Ramzan]

regressionplot will put the bars but where I am struggling is that

I can put

myrecessions = [1950, 1952; 1980, 1983];
recessionplot('recessions', myrecessions);

but don't know how to write it as

myrecessions = [November 1948 , October 1949 ; July 1953,May 1954];
recessionplot('recessions', myrecessions);

as the last one is giving an error. something wrong with the TIME variable. I have to spend a lot of time.

[Muhammad Ramzan]

@jonas sure I am waiting.

[jonas]

Sorry Muhammad, I don't have the economic toolbox so I cannot use the regeressionplot. From my understanding, you need to convert the values to the old date format (numeric) by using the datenum. I can help you with this, but you need to give me the raw data. Obviously, this line:

myrecessions = [November 1948 , October 1949 ; July 1953,May 1954];

will return an error. Give me the source of the data (excelsheet or txt) and I can help you format the data correctly for use in regressionplot.

[Muhammad Ramzan]

Please help me how to format the data correctly. Please

[Walter Roberson]

myrecessions = {'November 1948' , 'October 1949' ; 'July 1953',  'May 1954' ; 'August 1957', 'April 1958' ; 'April 1960' , 'February 1961' ; 'December 1969', 'November 1970' ; 'November 1973', 'March 1975' ; 'January 1980', 'July 1980' ; 'July 1981' , 'November 1982' ; 'July 1990' , 'March 1991' ; 'March 2001' , 'November 2001' ; 
'December 2007' , 'June 2009' };

recessions_datenum = reshape(datenum(myrecessions(:), 'mmmm yyyy'),size(myrecessions));

recessionplot('recessions', recessions_datenum);

But you need to change how you read your data:

mydata = xlsread('MacroData.xlsx');
t = mydata(:,1);
TIME = datenum([floor(t), round(mod(t,1)*30-2), 0*t+1]);  %converts quarters from .1, .2, .3, .4 into appropriate months
y = mydata(:,2);

[Muhammad Ramzan]

thanks

[Muhammad Ramzan]

@ Walter Roberson I want to have years on x-axis like from 1948 to 2011. Please help

[Walter Roberson]

mydata = xlsread('MacroData.xlsx');
t = mydata(:,1);
TIME = datenum([floor(t), round(mod(t,1)*30-2), 0*t+1]);  %converts quarters from .1, .2, .3, .4 into appropriate months
y = mydata(:,2);

myrecessions = {'November 1948' , 'October 1949' ; 'July 1953',  'May 1954' ; 'August 1957', 'April 1958' ; 'April 1960' , 'February 1961' ; 'December 1969', 'November 1970' ; 'November 1973', 'March 1975' ; 'January 1980', 'July 1980' ; 'July 1981' , 'November 1982' ; 'July 1990' , 'March 1991' ; 'March 2001' , 'November 2001' ; 
'December 2007' , 'June 2009' };

recessions_datenum = reshape(datenum(myrecessions(:), 'mmmm yyyy'),size(myrecessions));

figure(3)
plot(TIME,y)
recessionplot('recessions', recessions_datenum); 

datetick('x','yyyy')
xlim(datenum([1948 1 1; 2011 12 31]))

Tested. But you should re-check which column of data you want to plot: before it was column 7 but you seem to have switched to column 2.

Answer 2

[Peter Perkins]

If possible, use datetimes, not datenums. Jonas' answer seems good, except I think it isn't correct when dealing with the non-standard way that quarters are encoded as fractional years (as tenths!). I thik this would do it:

y = floor(t);
q = 10*years(mod(t,1)); % maybe even round this?
ts = datetime(y,1,1) + calquarters(q);

[jonas]

Good detail :)

You are right in that my original code was incorrect. Perhaps this would work:

year = floor(t);
fyear = years(mod(t,1));
ts=datetime(year,1,1)+fyear;

returns the following for t=[1990 1990.1];

ans =

2×1 datetime array

   01-Jan-1990 00:00:00
   06-Feb-1990 12:34:55

which should be about one 10th of a year...or am I missing something?

[Peter Perkins]

I interpreted "my data is date, that is year , quarter" as meaning .1 for Q1, .2 for Q2, etc. I may be wrong.

But in any case, adding a numeric value to a datetime treats the number as a datenum. You code, I think, wants to treat it as a fractional year, and that's problematic, because how long is one tenth of 2018 and how long is one tenth of 2020? That's why calyears requires integer values as inputs. You've used the years function, which does allow fractions, but it does not account for leap days, and in fact:

   Y = years(X) returns an array of durations with each element equal to the
   number of exact fixed-length (i.e. 365.2425 day) years in the corresponding
   element of X. Y is the same size as X. X may contain non-integer values.

   To create an array of calendar years that account for leap days when used in
   calendar calculations, use the CALYEARS function.

years is really meant as a convenience when you are dealing with very long time spans -- if you want a fixed-length unit of time to express a long duration, 100 "standard" years is easier to understand than 3.1557e+09 seconds. If you are doing a calculation that requires exact numbers, then "three calendar years" doesn't cut it -- the exact length depends on which three years you are talking about. So years(3) is an exact length of time, while calyears(3) is a sort of lazy evaluation that has no unique meaning until you add it to a date.

If you are dealing with calendar arithmetic calyears (and for the same reason, caldays) is what you want to use.

[Walter Roberson]

The input data had year numbers and .1 .2 .3 .4 but no .5 or higher fraction, and the question stated "quarters".

[jonas]

Thanks guys, I did not realize the fraction refered to quarter.

@Peter: Thanks a lot for the elaborate explanation. Did not know about calyear, which seems great for dealing with those annoying leap years!