I have 2 entities: Components & SurveyReadingWeb that have a one-to-many relationship.
I have saved Components data in core data database; but while saving SurveyReadingWeb -- in a for loop -- I have to fetch Components data entity by passing component id and setting the surveyreadings isComponentexists relationship, like in the code below for 8000 records. This process is taking too much time, nearly 7 minutes. How can I reduce the time?
for item in items {
autoIncrementId = autoIncrementId + 1
print("reading items parsed:- \(item.SurveyReadingId), \(autoIncrementId)")
let reading : SurveyReadingWeb? = NSEntityDescription.insertNewObject(forEntityName: Constants.EntityNames.kSURVEYREADINGWEB, into: self.managedContext) as? SurveyReadingWeb
reading?.surveyId1 = Int32(autoIncrementId)
reading?.surveyId = Int32(item.SurveyId) ?? 0
reading?.readingData = item.CH4
reading?.surveyDateTime = item.SurveyReadingDateTime
reading?.latitude = item.Latitude
reading?.longitude = item.Longitude
reading?.serialNumber = item.SerialNumber
reading?.descriptionText = item.Description
reading?.componentName = item.Description
reading?.componentId = Int32(item.ComponentId) ?? 0
reading?.readingTypeId = Int32(item.ReadingTypeID) ?? 0
reading?.readingTypeDetails = item.ReadingTypeDetails
reading?.currentLatitude = item.CurrentLatitude
reading?.currentLongitude = item.CurrentLongitude
reading?.hdop = item.HDOP
reading?.vdop = item.VDOP
reading?.componentDistance = item.ComponentDistance
reading?.facilityId = Int32(item.ProjectId) ?? 0
reading?.posted = 1
reading?.readyToSync = 1
reading?.isComponentExists = DatabaseManager.sharedManager.getCompNameFromID(compID: Int32(item.ComponentId) ?? 0)
}
saveContext()
func getCompNameFromID(compID : Int32) -> Components? {
var component : Components? = nil
let fetchRequest : NSFetchRequest<Components> = Components.fetchRequest()
fetchRequest.predicate = NSPredicate(format: "componentId == %ld", compID)
do {
let searchResults = try managedContext.fetch(fetchRequest)
component = (searchResults.first) ?? nil
} catch {
}
return component ?? nil
}
You can reduce the time dramatically if you add an NSCache instance to cache compID:Components key value pairs.
In getCompNameFromID check if the compID exists in the cache. If yes get the value from the cache (very fast), if not fetch the record and save it for the compID in the cache.
And use the convenient SurveyReadingWeb(context: initializer to get rid of all the ugly question marks, however the performance benefit is rather tiny.
I couldn't find a solution to this, I'm grabbing data from firebase and one of the fields is a timestamp which looks like this -> 1522129071. How to convert it to a date?
Swift example (works) :
func readTimestamp(timestamp: Int) {
let now = Date()
let dateFormatter = DateFormatter()
let date = Date(timeIntervalSince1970: Double(timestamp))
let components = Set<Calendar.Component>([.second, .minute, .hour, .day, .weekOfMonth])
let diff = Calendar.current.dateComponents(components, from: date, to: now)
var timeText = ""
dateFormatter.locale = .current
dateFormatter.dateFormat = "HH:mm a"
if diff.second! <= 0 || diff.second! > 0 && diff.minute! == 0 || diff.minute! > 0 && diff.hour! == 0 || diff.hour! > 0 && diff.day! == 0 {
timeText = dateFormatter.string(from: date)
}
if diff.day! > 0 && diff.weekOfMonth! == 0 {
timeText = (diff.day == 1) ? "\(diff.day!) DAY AGO" : "\(diff.day!) DAYS AGO"
}
if diff.weekOfMonth! > 0 {
timeText = (diff.weekOfMonth == 1) ? "\(diff.weekOfMonth!) WEEK AGO" : "\(diff.weekOfMonth!) WEEKS AGO"
}
return timeText
}
My attempt at Dart:
String readTimestamp(int timestamp) {
var now = new DateTime.now();
var format = new DateFormat('HH:mm a');
var date = new DateTime.fromMicrosecondsSinceEpoch(timestamp);
var diff = date.difference(now);
var time = '';
if (diff.inSeconds <= 0 || diff.inSeconds > 0 && diff.inMinutes == 0 || diff.inMinutes > 0 && diff.inHours == 0 || diff.inHours > 0 && diff.inDays == 0) {
time = format.format(date); // Doesn't get called when it should be
} else {
time = diff.inDays.toString() + 'DAYS AGO'; // Gets call and it's wrong date
}
return time;
}
And it returns dates/times that are waaaaaaay off.
UPDATE:
String readTimestamp(int timestamp) {
var now = new DateTime.now();
var format = new DateFormat('HH:mm a');
var date = new DateTime.fromMicrosecondsSinceEpoch(timestamp * 1000);
var diff = date.difference(now);
var time = '';
if (diff.inSeconds <= 0 || diff.inSeconds > 0 && diff.inMinutes == 0 || diff.inMinutes > 0 && diff.inHours == 0 || diff.inHours > 0 && diff.inDays == 0) {
time = format.format(date);
} else {
if (diff.inDays == 1) {
time = diff.inDays.toString() + 'DAY AGO';
} else {
time = diff.inDays.toString() + 'DAYS AGO';
}
}
return time;
}
Your timestamp format is in fact in Seconds (Unix timestamp) as opposed to microseconds. If so the answer is as follows:
Change:
var date = new DateTime.fromMicrosecondsSinceEpoch(timestamp);
to
var date = DateTime.fromMillisecondsSinceEpoch(timestamp * 1000);
From milliseconds:
var millis = 978296400000;
var dt = DateTime.fromMillisecondsSinceEpoch(millis);
// 12 Hour format:
var d12 = DateFormat('MM/dd/yyyy, hh:mm a').format(dt); // 12/31/2000, 10:00 PM
// 24 Hour format:
var d24 = DateFormat('dd/MM/yyyy, HH:mm').format(dt); // 31/12/2000, 22:00
From Firestore:
Map<String, dynamic> map = docSnapshot.data()!;
DateTime dt = (map['timestamp'] as Timestamp).toDate();
Converting one format to other:
12 Hour to 24 Hour:
var input = DateFormat('MM/dd/yyyy, hh:mm a').parse('12/31/2000, 10:00 PM');
var output = DateFormat('dd/MM/yyyy, HH:mm').format(input); // 31/12/2000, 22:00
24 Hour to 12 Hour:
var input = DateFormat('dd/MM/yyyy, HH:mm').parse('31/12/2000, 22:00');
var output = DateFormat('MM/dd/yyyy, hh:mm a').format(input); // 12/31/2000, 10:00 PM
Use intl package (for formatting)
Full code for anyone who needs it:
String readTimestamp(int timestamp) {
var now = DateTime.now();
var format = DateFormat('HH:mm a');
var date = DateTime.fromMillisecondsSinceEpoch(timestamp * 1000);
var diff = now.difference(date);
var time = '';
if (diff.inSeconds <= 0 || diff.inSeconds > 0 && diff.inMinutes == 0 || diff.inMinutes > 0 && diff.inHours == 0 || diff.inHours > 0 && diff.inDays == 0) {
time = format.format(date);
} else if (diff.inDays > 0 && diff.inDays < 7) {
if (diff.inDays == 1) {
time = diff.inDays.toString() + ' DAY AGO';
} else {
time = diff.inDays.toString() + ' DAYS AGO';
}
} else {
if (diff.inDays == 7) {
time = (diff.inDays / 7).floor().toString() + ' WEEK AGO';
} else {
time = (diff.inDays / 7).floor().toString() + ' WEEKS AGO';
}
}
return time;
}
Thank you Alex Haslam for the help!
if anyone come here to convert firebase Timestamp here this will help
Timestamp time;
DateTime.fromMicrosecondsSinceEpoch(time.microsecondsSinceEpoch)
If you are using firestore (and not just storing the timestamp as a string) a date field in a document will return a Timestamp. The Timestamp object contains a toDate() method.
Using timeago you can create a relative time quite simply:
_ago(Timestamp t) {
return timeago.format(t.toDate(), 'en_short');
}
build() {
return Text(_ago(document['mytimestamp'])));
}
Make sure to set _firestore.settings(timestampsInSnapshotsEnabled: true); to return a Timestamp instead of a Date object.
To convert Firestore Timestamp to DateTime object just use .toDate() method.
Example:
Timestamp now = Timestamp.now();
DateTime dateNow = now.toDate();
As you can see in docs
Just make sure to multiply by the right factor:
Micro: multiply by 1000000 (which is 10 power 6)
Milli: multiply by 1000 (which is 10 power 3)
This is what it should look like in Dart:
var date = new DateTime.fromMicrosecondsSinceEpoch(timestamp * 1000000);
Or
var date = new DateTime.fromMillisecondsSinceEpoch(timestamp * 1000);
meh, just use https://github.com/andresaraujo/timeago.dart library; it does all the heavy-lifting for you.
EDIT:
From your question, it seems you wanted relative time conversions, and the timeago library enables you to do this in 1 line of code. Converting Dates isn't something I'd choose to implement myself, as there are a lot of edge cases & it gets fugly quickly, especially if you need to support different locales in the future. More code you write = more you have to test.
import 'package:timeago/timeago.dart' as timeago;
final fifteenAgo = DateTime.now().subtract(new Duration(minutes: 15));
print(timeago.format(fifteenAgo)); // 15 minutes ago
print(timeago.format(fifteenAgo, locale: 'en_short')); // 15m
print(timeago.format(fifteenAgo, locale: 'es'));
// Add a new locale messages
timeago.setLocaleMessages('fr', timeago.FrMessages());
// Override a locale message
timeago.setLocaleMessages('en', CustomMessages());
print(timeago.format(fifteenAgo)); // 15 min ago
print(timeago.format(fifteenAgo, locale: 'fr')); // environ 15 minutes
to convert epochMS to DateTime, just use...
final DateTime timeStamp = DateTime.fromMillisecondsSinceEpoch(1546553448639);
How to implement:
import 'package:intl/intl.dart';
getCustomFormattedDateTime(String givenDateTime, String dateFormat) {
// dateFormat = 'MM/dd/yy';
final DateTime docDateTime = DateTime.parse(givenDateTime);
return DateFormat(dateFormat).format(docDateTime);
}
How to call:
getCustomFormattedDateTime('2021-02-15T18:42:49.608466Z', 'MM/dd/yy');
Result:
02/15/21
Above code solved my problem. I hope, this will also help you. Thanks for asking this question.
I don't know if this will help anyone. The previous messages have helped me so I'm here to suggest a few things:
import 'package:intl/intl.dart';
DateTime convertTimeStampToDateTime(int timeStamp) {
var dateToTimeStamp = DateTime.fromMillisecondsSinceEpoch(timeStamp * 1000);
return dateToTimeStamp;
}
String convertTimeStampToHumanDate(int timeStamp) {
var dateToTimeStamp = DateTime.fromMillisecondsSinceEpoch(timeStamp * 1000);
return DateFormat('dd/MM/yyyy').format(dateToTimeStamp);
}
String convertTimeStampToHumanHour(int timeStamp) {
var dateToTimeStamp = DateTime.fromMillisecondsSinceEpoch(timeStamp * 1000);
return DateFormat('HH:mm').format(dateToTimeStamp);
}
int constructDateAndHourRdvToTimeStamp(DateTime dateTime, TimeOfDay time ) {
final constructDateTimeRdv = dateTimeToTimeStamp(DateTime(dateTime.year, dateTime.month, dateTime.day, time.hour, time.minute)) ;
return constructDateTimeRdv;
}
Assuming the field in timestamp firestore is called timestamp, in dart you could call the toDate() method on the returned map.
// Map from firestore
// Using flutterfire package hence the returned data()
Map<String, dynamic> data = documentSnapshot.data();
DateTime _timestamp = data['timestamp'].toDate();
Simply call this method to return your desired DateTime value in String.
String parseTimeStamp(int value) {
var date = DateTime.fromMillisecondsSinceEpoch(value * 1000);
var d12 = DateFormat('MM-dd-yyyy, hh:mm a').format(date);
return d12;
}
Example: if you pass the TimeStamp value 1636786003, you will get the result as
11-12-2021, 10:46PM
If you are here to just convert Timestamp into DateTime,
Timestamp timestamp = widget.firebaseDocument[timeStampfield];
DateTime date = Timestamp.fromMillisecondsSinceEpoch(
timestamp.millisecondsSinceEpoch).toDate();
I tested this one and it works
// Map from firestore
// Using flutterfire package hence the returned data()
Map<String, dynamic> data = documentSnapshot.data();
DateTime _timestamp = data['timestamp'].toDate();
Test details can be found here: https://www.youtube.com/watch?v=W_X8J7uBPNw&feature=youtu.be
Print DateTime, TimeStamp as string from Firebase Firestore:
Timestamp t;
String s;
DateTime d;
//Declaring Variables
snapshots.data.docs[index]['createdAt'] is Timestamp
? t = snapshots.data.docs[index]['createdAt']
: s =
snapshots.data.docs[index]['createdAt'].toString();
//check createdAt field Timestamp or DateTime
snapshots.data.docs[index]['createdAt'] is Timestamp
? d = t.toDate()
: s =
snapshots.data.docs[index]['createdAt'].toString();
print(s.toString()); //Print Date and Time if DateTime
print(d.toString()); //Print Date and Time if TimeStamp
Recently I've faced the same issue. so I'm using simple logic.
Very simple to Convert TimeStamp to DateTime. We can use this get TimeStamp to DateTime format.
In this example, I'm using Firebase.
import 'package:intl/intl.dart'; /// Import this line
TimeStamp timestamp = database.data()["date"] /// Firebase firestore date field value.
//Example Outputs:- Timestamp(seconds=1657706107, nanoseconds=261000000)
DateTime dateTime = timestamp.toDate(); /// It will be return Date and Time Both.
//Example Outputs:- 2022-07-13 15:25:07.261
String dateOnly = DateFormat('dd/MM/yyyy').format(dateTime); /// It will be only return date DD/MM/YYYY format
//Example Outputs:- 13/07/2022
In a single-line code
import 'package:intl/intl.dart'; /// Import this line
String dateOnly = DateFormat('dd/MM/yyyy').format(database.data()["date"].toDate()); /// It will be only return date DD/MM/YYYY format
//Example Outputs:- 13/07/2022
Thanks for visiting and pushing my reputation 😍
Happy Coding Journey...🤗
2022
Actually the Flutter team updated the Timestamp object.
Now if you want to convert from Timestamp to DateTime you can just use this code:
/*you Timestamp instance*/.toDate()
eg. Timestamp.now().toDate()
Viceversa if you want to convert from DateTime to Timestamp you can do:
Timestamp.fromDate(/*your DateTime instance*/)
eg. Timestamp.fromDate(DateTime.now())
Hope you'll find this helpfull.
All of that above can work but for a quick and easy fix you can use the time_formatter package.
Using this package you can convert the epoch to human-readable time.
String convertTimeStamp(timeStamp){
//Pass the epoch server time and the it will format it for you
String formatted = formatTime(timeStamp).toString();
return formatted;
}
//Then you can display it
Text(convertTimeStamp['createdTimeStamp'])//< 1 second : "Just now" up to < 730 days : "1 year"
Here you can check the format of the output that is going to be displayed: Formats
Timestamp has [toDate] method then you can use it directly as an DateTime.
timestamp.toDate();
// return DateTime object
Also there is an stupid way if you want really convert it:
DateTime.parse(timestamp.toDate().toString())
Long num format date into Calender format from:
var responseDate = 1637996744;
var date = DateTime.fromMillisecondsSinceEpoch(responseDate);
//to format date into different types to display;
// sample format: MM/dd/yyyy : 11/27/2021
var dateFormatted = DateFormat('MM/dd/yyyy').format(date);
// sample format: dd/MM/yyy : 27/11/2021
var dateFormatted = DateFormat('dd/MM/yyyy').format(date);
// sample format: dd/MMM/yyyy : 27/Nov/2021
var dateFormatted = DateFormat('dd/MMM/yyyy').format(date);
// sample format: dd/MMMM/yyyy : 27/November/2021
var dateFormatted = DateFormat('dd/MMMM/yyyy').format(date);
print("Date After Format = $dateFormatted");
Assuming you have a class
class Dtime {
int dt;
Dtime(this.dt);
String formatYMED() {
var date = DateTime.fromMillisecondsSinceEpoch(this.dt);
var formattedDate = DateFormat.yMMMMEEEEd().format(date);
return formattedDate;
}
String formatHMA() {
var time = DateTime.fromMillisecondsSinceEpoch(this.dt * 1000);
final timeFormat = DateFormat('h:mm a', 'en_US').format(time);
return timeFormat;
}
I am a beginner though, I hope that works.
There are different ways this can be achieved based on different scenario, see which of the following code fits your scenario.
Conversion of Firebase timestamp to DateTime:
document['timeStamp'].toDate()
(document["timeStamp"] as Timestamp).toDate()
DateTime.fromMillisecondsSinceEpoch(document['timeStamp'].millisecondsSinceEpoch);
Timestamp.fromMillisecondsSinceEpoch(document['timeStamp'].millisecondsSinceEpoch).toDate();
If timeStamp is in microseconds use:
DateTime.fromMicrosecondsSinceEpoch(timestamp * 1000000);
If timeStamp is in milliseconds use:
DateTime.fromMillisecondsSinceEpoch(timestamp * 1000);
Add the following function in your dart file.
String formatTimestamp(Timestamp timestamp) {
var format = new DateFormat('yyyy-MM-dd'); // <- use skeleton here
return format.format(timestamp.toDate());
}
call it as formatTimestamp(document['timestamp'])
I have the following problem with iOS calculations when the user is in different locales. Here in Europe the decimal point separator is a "," and in other locales it might be a ".". As long as the user is in a locale with a "." all calculations work fine, but when a comma is used instead I get an error. Here's the simple code so far:
if let expense = expenseTextField.text
let expenseValue = Double(expense)
let guests = guestTextField.text
let guestValue = Double(guests) {
let result = round((expenseValue / guestValue) * 100) / 100
resultLabel.text = priceString
//resultLabel.text = String(result)
} else {
resultLabel.text = "No values!"
}
I am pretty sure I have to use the numberFormatter as far as I understand other questions on here, but I don't get how to do this and the documentation doesn't provide a sample how to create a double or float from a string. I tried the following but I get an error stating that I cannot neither create doubles nor use these variables for calculations:
if let expense = expenseTextField.text
let expenseValue = String(expense),
let guests = guestTextField.text
let guestValue = String(guests) {
let expenseFormatter = NumberFormatter()
expenseFormatter.number(from: expenseValue)
let guestFormatter = NumberFormatter()
guestFormatter.number(from: guestValue)
let expenseDouble = Double(expenseFormatter)
let guestDouble = Double(guestFormatter)
let result = round((expenseDouble / guestDouble) * 100) / 100
resultLabel.text = priceString
} else {
resultLabel.text = "No values!"
}
I am not sure how to create real Doubles from those strings with numberFormatter and then use them in calculations.
Can someone give me a tip?
Thanks
The only thing you need is to write the method call correctly:
let expenseDouble = expenseFormatter.number(from: expenseValue)?.doubleValue ?? 0
let guestDouble = guestFormatter.number(from: guestValue)?.doubleValue ?? 0
A formatter/parser directly converts string to number. You then have to take the Double value from it. Note that parsing can fail and you have to solve the resulting optional in that case, e.g. using ?? 0.
I have an Array: var messageArray = [AnyObject]() and in that Array there is a single tuple that contains Dictionaries with 10 key/value paires (9 of them not important for the sort): var messageDetailDict = [String: AnyObject]()
Getting and setting those values all work correctly, however now I want to sort the Array by 1 of the values (not keys) of the Dictionary.
Example -> The Array has a tuple containing several Dictionaries:
The key in the Dictionary (which is the first element in the Array) is: 'ReceivedAt' which has a value of 21-03-2015
The key in the Dictionary (which is the second element in the Array) is: 'ReceivedAt' which has a value of 20-03-2015
The key in the Dictionary (which is the third element in the Array) is: 'ReceivedAt' which has a value of 15-03-2015
Now the Array should be sorted so that the values of 'ReceivedAt' will be sorted from earliest date, to the last date.
Hope this makes sense, but it's a bit difficult to explain. Thanks!
EDIT >>>>>
This is the println(messageArray) output:
[(
{
ConversationId = "94cc96b5-d063-41a0-ae03-6d1a868836fb";
Data = "Hello World";
Id = "eeb5ac08-209f-4ef0-894a-72e77f01b80b";
NeedsPush = 0;
ReceivedAt = "/Date(1439920899537)/";
SendAt = "/Date(1436620515000)/";
Status = 0;
},
{
ConversationId = "94cc96b5-d063-41a0-ae03-6d1a868836fb";
Data = "Hello World";
Id = "86b8766d-e4b2-4ef6-9112-ba9193048d9d";
NeedsPush = 0;
ReceivedAt = "/Date(1439921562909)/";
SendAt = "/Date(1436620515000)/";
Status = 0;
}
)]
And the received date is converted to a string with the following method (I do think however this is not important, as it is a time interval, and therefore OK to sort):
func getTimeStampFromAPIValue(dateTimeReceived: String) -> String {
let newStartIndex = advance(dateTimeReceived.startIndex, 6)
let newEndIndex = advance(dateTimeReceived.endIndex, -2)
let substring = dateTimeReceived.substringWithRange(newStartIndex..<newEndIndex) // ell
let receivedAtValueInInteger = (substring as NSString).doubleValue
let receivedAtValueInDate = NSDate(timeIntervalSince1970:receivedAtValueInInteger/1000)
//format date
var dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "dd-MM-yy hh:mm"
var dateString = dateFormatter.stringFromDate(receivedAtValueInDate)
return dateString
}
Since the values of ReceivedAt are timestamps as strings you could apply the following algorithm:
var sortedArray = messageArray.sorted { (dict1, dict2) in
// Get the ReceivedAt value as strings
if let date1String = dict1["ReceivedAt"] as? String,
let date2String = dict2["ReceivedAt"] as? String {
// Compare the date strings to find the earlier of the two
return date1String.compare(date2String) == .OrderedAscending
}
// Couldn't parse the date, make an assumption about the order
return true
}
Try this, change OrderedAscending with OrderedDescending if need in inverse order
messageArray.sortInPlace {
($0["ReceivedAt"] as! NSDate).compare($1["ReceivedAt"] as! NSDate) == .OrderedAscending
}
I read on stackoverflow that easiest way to convert a DateTime variable back to Excel date was simply to do:
let exceldate = int(DateTime)
Admittedly this was in c# and not f#. This is supposed to work as the decimals represent time and int part represents date. I tried this and f# comes back with the error:
The type 'DateTime' does not support a conversion to the type 'int'
So how do I convert back to excel date?
More specificly, I m trying to create a vector of month 1st for a period between start date and end date. Both vector output and start date and end date are floats, i.e. excel dates. Here my clumsy first attempt:
let monthlies (std:float) (edd:float) =
let stddt = System.DateTime.FromOADate std
let edddt = System.DateTime.FromOADate edd
let vecstart = new DateTime(stddt.Year, stddt.Month, 1)
let vecend = new DateTime(edddt.Year, edddt.Month, 1)
let nrmonths = 12 * (edddt.Year-stddt.Year) + edddt.Month - stddt.Month + 1
let scaler = 1.0 - (float(stddt.Day) - 1.0) / float(DateTime.DaysInMonth(stddt.Year , stddt.Month))
let dtsvec:float[] = Array.zeroCreate nrmonths
dtsvec.[0] <- float(vecstart)
for i=1 to (nrmonths-1) do
let temp = System.DateTime.FromOADate dtsvec.[i-1]
let temp2 = temp.AddMonths 1
dtsvec.[i] = float temp2
dtsvec
This doesnt work because of the conversion issue and is rather complicated and imperative.
How do I do the conversion? How can I do this more functionally? Thanks
Once you have the DateTime object, just call ToOADate, like so:
let today = System.DateTime.Now
let excelDate = today.ToOADate()
So your example would end up like so:
let monthlies (std:float) (edd:float) =
let stddt = System.DateTime.FromOADate std
let edddt = System.DateTime.FromOADate edd
let vecstart = new System.DateTime(stddt.Year, stddt.Month, 1)
let vecend = new System.DateTime(edddt.Year, edddt.Month, 1)
let nrmonths = 12 * (edddt.Year-stddt.Year) + edddt.Month - stddt.Month + 1
let scaler = 1.0 - (float(stddt.Day) - 1.0) / float(System.DateTime.DaysInMonth(stddt.Year , stddt.Month))
let dtsvec:float[] = Array.zeroCreate nrmonths
dtsvec.[0] <- vecstart.ToOADate()
for i=1 to (nrmonths-1) do
let temp = System.DateTime.FromOADate dtsvec.[i-1]
let temp2 = temp.AddMonths 1
dtsvec.[i] = temp2.ToOADate()
dtsvec
In regards to getting rid of the loop, maybe something like this?
type Vector(x: float, y : float) =
member this.x = x
member this.y = y
member this.xDate = System.DateTime.FromOADate(this.x)
member this.yDate = System.DateTime.FromOADate(this.y)
member this.differenceDuration = this.yDate - this.xDate
member this.difference = System.DateTime.Parse(this.differenceDuration.ToString()).ToOADate
type Program() =
let vector = new Vector(34.0,23.0)
let difference = vector.difference