Cannot use find() inorder to find the index of a time in datetime array

Hello,

I was trying to find the index of a particular time having datetime format (attached here as time.mat). I tried the usual find() inorder to find the index of an element but am constantly getting a 0×1 empty double column vector.

For example, I tried the following.

t=load('time.mat');
time=t.a;                                       % a: [101×1 datetime]
index = find(time=='02-Dec-2014 07:05:25')

which gives me

0×1 empty double column vector.

Not sure why that is happening even though '02-Dec-2014 07:05:25' is present as the last element in the array.

Thank you for any help.

Answer 1

[Matt J]

Because you have sub-second precision in "t.a",

t=load('time.mat');
t.a(end)

ans = datetime
   02-Dec-2014 07:05:25

seconds( t.a(end) - datetime('02-Dec-2014 07:05:25')) 

ans = 0.6015

[Mathan]

Oh ok, thank you! So is there any way to find the index of the element in this case?

[Matt J]

Find it based on what criterion? There is no exact match in the list. Do you want the closest element in t.a to '02-Dec-2014 07:05:25' ?

[Mathan]

Yea something sort of like that - a closest element would suffice actually.

[Matt J]

t=load('time.mat');
tmin=min(t.a);
time=seconds(t.a-tmin);    
N=numel(time);% a: [101×1 datetime]
index = interp1(time,1:N, seconds(datetime('02-Dec-2014 07:05:25')-tmin),'nearest')

[Mathan]

Thank you - it works!