How can I see the right labels on x-axis?

Hello everyone,

why do I got this error and I can't see the right labels on my plot?

Can anyone help me please?

Thank you.

load('GIULIA_MMEQ1.mat');
A=GIULIAMMEQ1.Var4;
B=str2double(A);
NEW= B * 10 * 0.35;
C=GIULIAMMEQ1.Dec1997;%array2table
C=replace(C,"';","");
C=datetime(C,'InputFormat','dd MMM yyyy'); %convert to datetime format

newTicks = datetime({'2000','2002','2004','2006','2008','2010','2012','2014','2016','2018'},'InputFormat','u');
xticks([2000,2002,2004,2006,2008,2010,2012,2014,2016,2018]);
xticks(newTicks);

Error using xticks (line 33)
Tick values must be a vector of increasing numeric values.

xticklabels(['2000','2002','2004','2006','2008','2010','2012','2014','2016','2018']);
hold on
plot(C,NEW) 

Answer 1

[Star Strider]

Without downloading the .mat file and running the entire code, this seems to work —

newTicks = datetime({'2000','2002','2004','2006','2008','2010','2012','2014','2016','2018'},'InputFormat','yyyy', 'Format','yyyy');

figure
plot(newTicks, rand(size(newTicks)))

.

[Pul]

@Star Strider But it doesn't work with my plot!

[Star Strider]

Try this —

LD = load('Pul GIULIA_MMEQ1.mat');
GIULIAMMEQ1 = LD.GIULIAMMEQ1;
% First10Rows = GIULIAMMEQ1(1:10,:);                                                          % Information
GIULIAMMEQ1.Dec1997 = datetime(GIULIAMMEQ1.Dec1997, 'InputFormat','dd MMM yyyy'''';');
% First10Rows2 = GIULIAMMEQ1(1:10,:);                                                         % Information
NEW = str2double(GIULIAMMEQ1.Var4) * 10 * 0.35;
newTicksc = {'2000','2002','2004','2006','2008','2010','2012','2014','2016','2018'};        % 'cell' Array
newTicks = datetime(newTicksc,'InputFormat','yyyy', 'Format','yyyy');                       % 'datetime' Array

figure
plot(GIULIAMMEQ1.Dec1997, NEW)
grid
xt = xticks;
newXTick = linspace(str2double(newTicksc{1}), str2double(newTicksc{end}), numel(newTicks));
set(gca, 'XTick',newTicks)

I cannot run that using the online Run feature because .mat files are too difficult to use with it. It works offlilne.

.

[Pul]

It worked. Thank you!

[Star Strider]

As always, my pleasure!

.

Answer 2

[Walter Roberson]

You have not plotted anything to this point.

newTicks = datetime({'2000','2002','2004','2006','2008','2010','2012','2014','2016','2018'},'InputFormat','u');

You create a vector of datetime values, but nothing has been plotted yet

xticks([2000,2002,2004,2006,2008,2010,2012,2014,2016,2018]);

You tell xticks to use a series of floating point numbers. Because you have not plotted anything yet, this use of floating point numbers for the tick positions tells MATLAB that the x axes should be created as a numeric axes (not as a datetime or map or polar axes)

xticks(newTicks);

You have already created ticks, so this command would be to change the ticks to something else. But the previous xticks() call forced the axes to numeric, and this xticks() is trying to use datetime ticks. You cannot use datetime() ticks on a numeric axes.

... Just skip the xticks() giving the numeric values.