How to sort by time

Hi,

I have below data,I want to select two data points above and below to the specified time.

2015/8/5 12:13    2
2015/6/13 22:13   5
2015/9/16 15:45   8
2015/7/23 17:05   15
2015/9/14 12:45   20
2015/6/17 21:44   26
2015/5/13 12:45   28

given time is: 2015/7/23 17:05, two data counts above and below which are more close to give time are"

My desired output:

2015/8/5 12:13   2
2015/6/13 22:13  5
2015/9/14 12:45  20
2015/6/17 21:44  26

many many thanks in advance,

Answer 1

[Andrei Bobrov]

T = readtable('20170916.txt','CollectOutput',1);
T.Var1 = strcat(T{:,1}(:,1),{' '},T{:,1}(:,2));
T.
t = datetime('2015/7/23 17:05','f','uuuu/MM/dd HH:mm')

z = abs(day(T{:,1} - t))
t = ~z;
y =  ~t.*(cumsum(t) + 1 );
n = numel(z);
kk = (1:n)';
s = false(n,1);
for ii = 1:2
    m = y == ii;
    p = kk(m);
    [~,v] = sort(z(m));
    s(p(v(1:2))) = true;
end
out = T(s,:)

out =
  4×2 table
          Date          data
    ________________    ____
    2015/08/05 12:13     2  
    2015/06/13 22:13     5  
    2015/09/14 12:45    20  
    2015/06/17 21:44    26

Answer 2

[dpb]

>> dnm=datetime(c(:,1),'format','yyyy/M/d HH:mm');                % convert date strings
>> target=datetime('2015/7/23 17:05','format','yyyy/M/d HH:mm');  % and the target date
>> [dnm,ix]=sort(dnm);                                            % order, keep index
>> idx=[find(dnm<target,2,'last');find(dnm>target,2,'first')]     % find closest two either side of target
idx =
   2
   3
   5
   6
>> c(ix(idx),:)               % look up originals based on presort index
ans = 
  '2015/6/13 22:13'    [ 5]
  '2015/6/17 21:44'    [26]
  '2015/8/5 12:13'     [ 2]
  '2015/9/14 12:45'    [20]
>>

Unlike the previous Answer this replaces, this doesn't assume the target time is identically one of those in the data vector (although that might be always so, this is more generic).

Also the previous note on sort wasn't so; not sure what was wrong that caused that symptom earlier...