Get the pieces of a date from a string - ios

How would you get the substring of a string that is dynamic? By this I mean that I am retrieving tweets and I want to extract different parts of the return value into a Month String, a Year int, a day int, and a time int. Here is what I am retrieving:
Sun Nov 17 00:15:47 +0000
How would I split it up even if the given value would change over time, as the tweet is on a index path of multiple table view cells, and the value of the creation date would be different for each one of the cells?

Your string represents a date, so the first thing you should do is convert it to an NSDate using an NSDateFormatter.
Then you can get the various elements of the date by creating an NSDateComponents instance via -[NSCalendar components:fromDate:], and accessing its month, day, and whatever other properties you need.

Related

How do you select all the rows between two values in SQLite?

I'm building an iOS app where I want to retrieve all the values from my database between two dates that the user picks. So for example, I want all the rows from the 1st of March to the 5th of March. Would look something like
SELECT * FROM MAIN WHERE DATE = '01/03/2020' AND ENDS ='05/03/2020'
So from that I would hope to retrieve all data from the 1st,2nd,3rd,4th and 5th of march. Any ideas on how to do this?
Thank you
Try to use comparison operators like:
DATE >= '01/03/2020' AND DATE <= '05/03/2020'
There are two issues:
Date types:
As Datatypes In SQLite Version 3 says:
2.2. Date and Time Datatype
SQLite does not have a storage class set aside for storing dates and/or times. Instead, the built-in Date And Time Functions of SQLite are capable of storing dates and times as TEXT, REAL, or INTEGER values:
TEXT as ISO8601 strings ("YYYY-MM-DD HH:MM:SS.SSS").
REAL as Julian day numbers, the number of days since noon in Greenwich on November 24, 4714 B.C. according to the proleptic Gregorian calendar.
INTEGER as Unix Time, the number of seconds since 1970-01-01 00:00:00 UTC.
Applications can chose to store dates and times in any of these formats and freely convert between formats using the built-in date and time functions.
So storing dates in a dd/MM/yyyy format (using the DateFormatter capitalization convention) is problematic because in the absence of a native date type, it’s going to store them as strings, and therefore all comparisons will be done alphabetically, not chronologically, sorting values like 03/10/2009 (or nonsense strings like 02foobar, for that matter) in between the strings 01/05/2020 and 05/05/2020.
If, however you store them as yyyy-MM-dd, then it just so happens that alphabetical comparisons will yield chronologically correct comparisons, too.
SQL syntax:
Once you have your dates in your database in a format that is comparable, then if you have all of your dates in a single column, you can use the BETWEEN syntax. For example, let’s say you stored all of your dates in yyyy-MM-dd format, then you could do things like:
SELECT * FROM main WHERE date BETWEEN '2020-03-01' AND '2020-03-05';
But needless to say, you can’t use this pattern (or any comparison operators other than equality) as long as your dates are stored in dd/MM/yyyy format.
If you want to show all the data that has values of column "date" between this two dates then:
Select *
from MAIN
where `date` between '01.03.2020' and '05.03.2020';
If you want to show all the data that has values of column "ends" between this two dates then:
Select *
from MAIN
where ends between '01.03.2020' and '05.03.2020';
If you want to show all the data that has values of columns "date" and "ends" between this two dates then:
Select *
from MAIN
where ends between '01.03.2020' and '05.03.2020'
and `date` between '01.03.2020' and '05.03.2020';
Here is a demo

Converting Date to "/Date(631148400000+0100)/" string in Swift

I need to convert Swift Date object to date ticks string like "/Date(631148400000+0100)/".
The following link tells me how to convert date ticks string to Date object but not the vice-versa:
How to convert date like \/Date(1440156888750-0700)\/ to something that Swift can handle?
How can I do that?
Thanks in advance.
From Stand-Alone JSON Serialization:
DateTime values appear as JSON strings in the form of "/Date(700000+0500)/", where the first number (700000 in the example provided) is the number of milliseconds in the GMT time zone, regular (non-daylight savings) time since midnight, January 1, 1970. The number may be negative to represent earlier times. The part that consists of "+0500" in the example is optional and indicates that the time is of the Local kind - that is, should be converted to the local time zone on deserialization. If it is absent, the time is deserialized as Utc. The actual number ("0500" in this example) and its sign (+ or -) are ignored.
And from Use JSON.NET to parse json date of format Date(epochTime-offset)
... In this screwy format, the timestamp portion is still based solely on UTC. The offset is extra information. It doesn't change the timestamp. You can give a different offset, or omit it entirely and it's still the same moment in time.
So the number of ticks is the number of milliseconds since Januar 1, 1970 GMT. Adding a time zone specification would only change how the
date is presented locally in .NET, and one can simply omit that part
when generating a JSON date string:
extension Date {
var jsonDate: String {
let ticks = lround(timeIntervalSince1970 * 1000)
return "/Date(\(ticks))/"
}
}
Example:
print(Date().jsonDate) // /Date(1481446227993)/

Data retrieving from sqlite DB between two dates - using objective c

I am using the below query with date filtering, but I am getting wrong result.
SELECT * FROM TRANSACTIONSHISTORY
WHERE DATE > "29-01-2015 12:00:00"
AND DATE < "30-01-2015 00:00:00" AND USERID=abc
I am getting result with date column with value of 29-Jan-2016 records, what am I missing here, can any one help me to get out of this value.
The date format in your SQL will not work because SQLite doesn't have a native datetime type, so it's generally stored either as a string, in YYYY-MM-DD HH:MM:SS.SSS format, or as an numeric value representing the number of seconds since 1970-01-01 00:00:00 UTC. See date and time types on SQLite.org. Note that if you're using the string representation that the sequence is year, month, day (which, when sorting/querying this string field, the this alphanumeric string will sort correctly by year first, then month, and then day, which is critical when doing queries like yours).
If you really stored dates in the database as a string in the DD-MM-YYYY HH:MM:SS format, you should consider changing the format in which you saved the values into one of the approved date formats. It will make the date interactions with the database much, much easier, allowing queries like the one you asked for (though, obviously, with DD-MM-YYYY replaced with YYYY-MM-DD format).
You have cast your string to Date
SELECT * FROM TRANSACTIONSHISTORY WHERE DATE between Datetime('29-01-2015 12:00:00') and Datetime('30-01-2015 00:00:00') AND USERID=abc
The first answer is exactly what you need. What you did in your code would be comparing strings using ASCII values.
I would recommend you to use the linux time stamps like: 1453818208, which is easier to save and compare. In addition, it can always be translated to human-readable dates like: 29-01-2015 12:00:00.
SELECT * FROM TRANSACTIONSHISTORY
WHERE DATE > "29-01-2015 12:00:00"
AND DATE < "30-01-2015 00:00:00" AND USERID=abc
I hope this helps you :)
Try this first try without Time,after that try date and time both , Hope i will work for you
SELECT TRANSACTIONSHISTORY
FROM SHIPMENT
WHERE DATE
BETWEEN '11-15-2010'
AND '30-01-2015'
// you can try this one also
SELECT * FROM TRANSACTIONSHISTORY WHERE DATE BETWEEN "2011-01-11" AND "2011-8-11"

Getting a NSDate object from a string

Before flagging this question as a duplicate, please read on.
I need to compare two NSDates. A date I get from a server with the current date.
From NSDate.date() I get this date 2014-09-25 12:48:23 +0000 which is wrong (the time part). I needed to add 5 hours to get the current time so I did the following.
let formatter = NSDateFormatter()
formatter.dateFormat = "yyyy-MM-dd hh:mm:ss ZZZZZ"
let dateString = formatter.stringFromDate(NSDate.date())
The result is the correct date - 2014-09-25 06:21:56 +05:30
But there's a little hitch. This date is a String, not a NSDate. I need it to be a NSDate object to compare it with another date.
I tried converting it back like this,
let date = formatter.dateFromString(dateString)
And I get a wrong result - 2014-09-25 00:55:53 +0000. I tried passing the date string to a new NSDateFormatter to see if that works but again I still I get the wrong date.
My question is, how can I convert this date string to a NSDate object which also retains the correct time.
Thank you.
You are thoroughly confused about NSDate.
An NSDate is a point in time. It has no time zone information. If we both call [NSDate date] right now, we will get the same NSDate, even when you are in India and I'm in the UK. That's intentional. It's the same time. The time displayed on my watch and on your watch is different, but NSDate is the same. You can't convert NSDate to an "Indian" date.
You use calendars and timezones to convert NSDates to strings that you display to a user, in the way your users expect it. That's what you have done. You got a string that makes sense to Indian users. If an Indian user types a time, you take that string and convert it to an NSDate. The NSDate will be in Universal time. If you and I both typed in the time on our watch right now and converted it, you would type a time that looks like 5 1/2 hours earlier than mine. But it's the same time. If you convert it to NSDate, we will both get the exact same NSDate.
So how do you change your NSDate? Quite simple: You don't. NSDate is absolute time, independent of your location on earth.
Upon further Googling, I came across this post. The method described in it does exactly what I want. The original code is in Objective-C and since my question is in Swift, I'm going to post its Swift translation. \
func toLocalTime() -> NSDate {
let timeZone = NSTimeZone.localTimeZone()
let seconds = timeZone.secondsFromGMTForDate(self)
return NSDate(timeInterval: Double(seconds), sinceDate: self)
}
I added these as extension methods of NSDate so you can simply call them like this.
NSDate.date().toLocalTime()
You can compare two dates using any of the following NSDate functions: compare, earlierDate, laterDate, isEqualToDate. You should not compare date strings (oh, goodness, no, think of the nightmare); convert 'date strings' into 'NSDate' as soon as inputed.
In order to compare two dates that arose from strings correctly, you'll need the date strings to be unambiguous. In practice, that requires the date to have a time zone attached. If your server isn't providing a time zone and can't be modified to provide one, then you'll be forced to assume one (which would typically be the time zone where the server is located, assuming one server).

Convert SPSS string variable to numeric and date

I have the date variable which is in string format. I need to convert this to numeric or date format. How can I do this?
Example:
var1
2010/07/09
2010/07/16
Thanks,
Tanuvi
If you read in the date value as a string, you can use Transform > Date and Time Wizard to convert it to an SPSS date variable. Although date variables look like dates in various formats, they are actually represented as the number of seconds since 1582 and can consist of calendar and time information.

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