Convert time string to 24 hour format then into Decimal using current time clock

조회 수: 5 (최근 30일)
I am trying to convert the variable AST from a string to a number in 24 hour format. I would then like to store AST as a new variable, call it 'ASTdec' in decimal i.e AST at 13:30 = 13.5 so that I can manipulate it with other eqns. AST is the solar time, converted from regular clock time.
background code:
c = clock();
tsNow = datenum(c);
tsStart = datenum([c(1) 1 1 0 0 0]);
daysInYear = tsNow - tsStart;
DayOfYear = floor(daysInYear)+1;
get current LST time in 24 hour format:
datestr(now);
d = rem(now,1);
datestr(d);
time = datestr(d, 'HH:MM');
get apparent solar time AST:
B = 360/365*(DayOfYear-81);
EoT = 9.87*sind(2*B)-7.53*cosd(B)-1.5*sind(B);
Correction = EoT - (4*(0-3.173));
Declination = 23.45*sind((360/365)*(284+DayOfYear));
AST = datestr(d - datenum([0 0 0 0 Correction 0]));
Tried using:
ASTVec = datevec(AST, 'HH:MM');
SolarMinutes = ASTVec(5);
SolarHours = ASTVec(4);
to get the vector and then do manipulation with the vector cells to get my decimal but SolarHours are not in 24 hr format because the string is not in 24 hour format. Variable
Correction
is already a value of time expressed in decimal and is used to define AST.

채택된 답변

Walter Roberson
Walter Roberson 2013년 11월 15일
It looks to me like,
ASTVec = datevec(d - Correction/(24*60));
  댓글 수: 3
Walter Roberson
Walter Roberson 2013년 11월 15일
Minutes if I have correctly understood your Correction to be in minutes. You would continue on with your existing code,
SolarMinutes = ASTVec(5);
SolarHours = ASTVec(4);
P
P 2013년 11월 15일
Got it. Because I wasn't actually in 24 hour time when running the script I wasn't sure I was getting the correct answer. Thank you.

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