What's the nearest equivalent of DateTime.TryParse() in classic asp? - datetime

I need to do some validation in classic asp on some user-supplied strings to make sure they are valid dates. How can I parse the string to a date while checking for type mismatch exceptions...
So far it's looking alot harder than I thought!

You can use IsDate for this.
This determines whether the value is a date or can be converted to a date.
E.g. (from here),
x = "January 12, 2009"
if IsDate(x) then
msgbox(CDate(x))
end if
Output:
1/12/2009

Related

Date conversion handling YYYY-MM-DD HH:MM:SS.SSS

My source is a file and loading into SQL Server table. I'm working on a scenario where i have to convert a string '2019-04-02T21:24:00.065' to informatica datetime format.
I tried below expression but some times its failing due to we are not receiving milliseconds from our source file in few occasions.
IIF(NOT ISNULL(DATEFIELD),TO_DATE(SUBSTR (DATEFIELD, 0, 10) || ' ' || SUBSTR(DATEFIELD, 12, 12), 'YYYY-MM-DD HH24.MI.SS.US'),NULL)
I'm looking for a permanent fix to handle all types of datetime formats regardless of what we receive in the file.
Well... I'm sorry to say, but there is no magic component that will recognize all possible date and time formats (including e.g. verbal in swahili).
You will need to detect the format for yourself. You can use a DECODE function, like e.g.:
DECODE(True,
IS_DATE(your_input_port, 'DD/MM/YYYY'), TO_DATE(your_input_port, 'DD/MM/YYYY'),
...)
If you are completely sure that only seconds/milliseconds are the missing part, you can check for length, if less than 12, use RPAD to the second part of your SUBSTR with missing format, or you can use decode as suggested by #maciejg and write code for all possible date formats.
Thanks for your inputs guys. Since we are not sure which date format we are receiving , we decided to go with a simple fix for this. I have changed the target field to varchar and simply replacing the T with ' ' value since this a staging mapping.
Again thanks for your time and inputs.

ISO datetime with timezone issue

I am just printing the ISO datetime with timezone as per the below documentation
http://support.sas.com/documentation/cdl/en/lrdict/64316/HTML/default/viewer.htm#a003169814.htm
This is my code
TimeZone tz = TimeZone.getTimeZone("UTC");
DateFormat df = new SimpleDateFormat("yyyy-mm-dd'T'hh:mm:ss.nnnnnn+|-hh:mm");
df.setTimeZone(tz);
dateTimeWithTimeZone = df.format(new Date());
However i am getting this exception
Illegal pattern character 'n'
I cant use this format directly in Java ?
java.time
dateTimeWithTimeZone = Instant.now().toString();
System.out.println(dateTimeWithTimeZone);
When I ran this snippet just now, I got this output:
2019-03-18T22:28:13.549319Z
It’s not clear from the page you link to, but it’s an ISO 8601 string in UTC, so should be all that you need. I am taking advantage of the fact that the classes of java.time produce ISO 8601 output from their toString methods. The linked page does show the format with hyphens, T and colons (2008-09-15T15:53:00+05:00), it shows another example with decimals on the seconds (15:53:00.322348) and a third one with Z meaning UTC (20080915T155300Z), so I would expect that the combination of all three of these would be OK too.
The format you used in the quesiton seems to try to get the offset as +00:00 rather than Z. If this is a requirement, it’s only a little bit more complicated. We are using an explicit formatter to control the variations within ISO 8601:
DateTimeFormatter iso8601Formatter
= DateTimeFormatter.ofPattern("uuuu-MM-dd'T'HH:mm:ss.SSSSSSxxx");
dateTimeWithTimeZone = OffsetDateTime.now(ZoneOffset.UTC).format(iso8601Formatter);
System.out.println(dateTimeWithTimeZone);
2019-03-18T22:28:13.729711+00:00
What went wrong in your code?
You tried to use the formatting symbols from your source with SimpleDateFormat. First, you should never, and especially not in Java 8 or later, want to use SimpleDateFormat. That class is notoriously troublesome and long outdated. Second, some of its format pattern letters agree with the symbols from your source, some of them don’t, so you cannot just use the symvol string from there. Instead you need to read the documentation and find the correct format pattern letters to use for year, month, etc. And be aware that they are case sensitive: MM and mm are different.
Link
Oracle Tutorial: Date Time
explaining how to use java.time.

ColdFusion - DateTime Format with GMT offset

I am using ColdFusion 10 to make some REST calls and the date returned is using a GMT offset.
Example: 2013-03-25T14:30:40-04:00
I need this formatted for 2 purposes:
Screen Display so it looks something like mm/dd/yyyy hh:mm:ss
To Insert into mySQL.
I have tried a variety of the CF time/date functions but continue to get the "is not a valid date format"
I thought maybe the #ParseDateTime(i.submitted_at,"pop")# would handle it with POP but same issue.
Spent a few hours now trying multiple variations and googling around now just going in circles. Any ideas would be greatly appreciated.
Thanks!
Have a look at the UDF DateConvertISO8601() on CFLib.
DateConvertISO8601(ISO8601dateString, targetZoneOffset) on CFLib
Description:
This function take a string that holds a date in ISO 8601 and converts it to ODBC datetime, but could be adapted to convert to whatever you like. It also will convert to a datetime in a timezone of your choice by specifying the offset, i.e. it could take a datetime in GMT and convert to PT. See http://www.w3.org/TR/NOTE-datetime for description of ISO 8601, the International Standard for the representation of dates and times.
Return Values:
Returns a datetime.
The source code is viewable at the link I provided.
This, 2013-03-25T14:30:40-04:00, is a string. If you run this:
x = left(2013-03-25T14:30:40-04:00, 19);
you get 2013-03-25T14:30:40. You can use the replace function to replace the T with a space. You can then to this
DateTimeVar =parsedatetime('2013-03-25 14:30:40');
Now you have a datetime variable that you can format. If necessary you can do a datediff with the offset from GMT.
This is an informational answer, not a direct answer to the question.
ColdFusion 11 has updated the ParseDateTime() function so that it will correctly convert the ISO-8601 date/time strings to a ColdFusion datetime object.
With a number of remote requests and responses, the date / time values can often be returned in ISO format. In your case, the mask looks like this:
YYYY-MM-DDThh:mm:ssTZD (eg 1997-07-16T19:20:30+01:00)
In this ISO format, the T string is a literal representation of a marker where the time stamp starts in the string (with the offset following directly).
Below is a reusable function that will convert an ISO date format into a useable ColdFusion date time object:
<cffunction name="ISOToDateTime" access="public" returntype="string" output="false"
hint="Converts an ISO 8601 date/time stamp with optional dashes to a ColdFusion
date/time stamp.">
<cfargument name="Date" type="string" required="true" hint="ISO 8601 date/time stamp." />
<cfreturn ARGUMENTS.Date.ReplaceFirst(
"^.*?(\d{4})-?(\d{2})-?(\d{2})T([\d:]+).*$",
"$1-$2-$3 $4"
) />
</cffunction>
You can then call the function like so to output or return a ColdFusion-friendly version of the date time:
ISOToDateTime( "2013-03-25T14:30:40-04:00" )
That function is courtesy of Ben Nadel. The original blog post can be found here:
http://www.bennadel.com/blog/811-Converting-ISO-Date-Time-To-ColdFusion-Date-Time.htm
You can also convert the date time value using the offset, if required. Again, Ben Nadel has a great blog post outlining how to accomplish this:
http://www.bennadel.com/blog/1595-Converting-To-GMT-And-From-GMT-In-ColdFusion-For-Use-With-HTTP-Time-Stamps.htm
CF10 can use this code as stated in the example of the parseDateTime() doc.
<cfset string = "1997-07-16T19:20:30+01:00">
<cfset date = parseDateTime(string, "yyyy-MM-dd'T'HH:mm:ssX")>

Package to parse dates in Common Lisp?

I'm writing a simple web scraper in Common Lisp (SBCL) as a learning exercise, & would like to sort by date. To do this, I'll need to parse dates in the format "MM/DD/YYYY" into universal time.
I could simply tokenise the string & pass the bits into encode-universal-time, but I figure that there must be a built-in function (or popular third-party package) for date parsing. I'd greatly appreciate someone recommending one :-)
This answer is very late but the local-time library is featureful and widely used. It is based on the article The long painful history of time.
It supports :
Time and date arithmetic
ISO 8601 timestring formatted output and parsing
Reader macros to embed timestrings directly in code
Timezone handling (will read unix tzfile format)
Conversion between universal and unix time epochs
Julian date calculation
See the net-telent-date and simple-date-time libraries for Common Lisp. The former has a parse-time function you can use (see parse-time.lisp). Both are included in the QuickLisp library collection.
You could try net-telent-date, which has PARSE-TIME which I think will do what you want.
It's now 2022, and net-telent-date is on github and is also deprecated. Better to find something else.
Many implementations have a UNIX interface and, in same cases, this includes the strptime function.
Antik handles dates and times and includes date/time parsers. The result is a "timepoint" which by default is UTC (CL's "universal-time" is something different, but it can be converted to that).
I use local-time and cl-date-time-parser:
edit: and chronicity for parsing natural language dates and times.
(local-time:parse-timestring "2019-11-13T18:09:06.313650+01:00") ;; OK
(local-time:parse-timestring "2019-11-13") ;;OK
This fails with local-time by default:
(local-time:parse-timestring "2019/11/13")
but it works with Chronicity:
(chronicity:parse "2019/11/13")
#2019-11-13T00:00:00.000000+01:00
and we can set the date separator of local-time to "/":
(local-time:parse-timestring "2019/11/13" :date-separator #\/) ;; OK
There is also the time and datetime separators.
Now a format like ""Wed Nov 13 18:13:15 2019" will fail. We'll use the
cl-date-time-parser library:
(cl-date-time-parser:parse-date-time "Wed Nov 13 18:13:15 2019")
;; 3782657595
;; 0
It returns the universal time which, in turn, we can ingest with the
local-time library:
(local-time:universal-to-timestamp *)
;; #2019-11-13T19:13:15.000000+01:00

DateTime issue on different platforms (.NET 2.0)

On a 32 bit OS, with an Intel processor,
DateTime e.g. 2/17/2009 12:00:00 AM
Notice that it is: mm/DD//yyyy
On a 64 bit OS, with an AMD processor,
DateTime e.g. 17-02-2009 00:00:00
Now when I try to parse the 1st format, it throws an error on the 2nd platform.
That means - DateTime.Parse("2/17/2009 12:00:00 AM") - throws an error - cannot convert.
whereas, on the same platform,
DateTime.Parse("17/2/2009 12:00:00 AM") works! That means DD/MM is fine, MM/DD is not.
What is causing this? The 64-bit OS? The processor?
How do I get rid of the problem?
DateTimes themselves don't have formats. You parse them or format them into strings. (It's like numbers - integers aren't stored in hex or decimal, they're just integers. You can format them in hex or decimal, but the value itself is just a number.)
The format will depend on the culture of the operating system (or more accurately, the culture of the thread, which is typically the same as the operating system one).
Personally I like to explicitly set the format I use for either parsing or formatting, unless I'm actually displaying the string to the user and know that the culture is appropriate already.
Check your "Date and time formats" in the "Region and Language" control panel.
Also, if you want DateTime to generate a specific format, don't just call plain ToString(), but pass it a parameter indicating the format you want. Similarly, if you know the format of the date you are asking it to parse, call TryParseExact(), and tell it the format you are providing.
See also MSDN's Standard Date and Time Format Strings

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