Adding time to date

  • Thread starter Thread starter Saga
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Saga

I need to add the time a a date, specifically, the current date.
This seemed easy enough, but I found that thi wasn't so.

As in input I get 3 or 4 digits representing the date. Valid
input string are:

"0344", "1102", "456"

The minutes are always 2 digits, but the hour can be either
1 or 2 digits.

What I did was first come up with a function to normalize
the input string which formats it hh:mm:

private function sSetTime(byval strTime as string) as integer

strTime = strTime.ToString("D4")

Return strTime.Substring(0, 2) & ":" & strTime.Substring(2, 2)

end function

Next is my date variable where I am going to keep the date
and time:

dim dteEnd as date = date.today()
dim strT as string = "345" 'For example
Now I add the time:

dteEnd = dteEnd.AddHours(
Convert.ToDouble(sSetTime(strT.Split(":".ToCharArray()).GetValue(0).ToString()))
)

And add the minutes

dteEnd = dteEnd.AddMinutes(
Convert.ToDouble(sSetTime(strT.Split(":".ToCharArray()).GetValue(1).ToString()))
)

Is there a better way to do this? <g>
Thanks, Saga
 
I need to add the time a a date, specifically, the current date.
This seemed easy enough, but I found that thi wasn't so.

As in input I get 3 or 4 digits representing the date. Valid
input string are:

"0344", "1102", "456"

The minutes are always 2 digits, but the hour can be either
1 or 2 digits.

What I did was first come up with a function to normalize
the input string which formats it hh:mm:

private function sSetTime(byval strTime as string) as integer

strTime = strTime.ToString("D4")

Return strTime.Substring(0, 2)& ":"& strTime.Substring(2, 2)

end function

Next is my date variable where I am going to keep the date
and time:

dim dteEnd as date = date.today()
dim strT as string = "345" 'For example
Now I add the time:

dteEnd = dteEnd.AddHours(
Convert.ToDouble(sSetTime(strT.Split(":".ToCharArray()).GetValue(0).ToString()))
)

And add the minutes

dteEnd = dteEnd.AddMinutes(
Convert.ToDouble(sSetTime(strT.Split(":".ToCharArray()).GetValue(1).ToString()))
)

Is there a better way to do this?<g>
Thanks, Saga
Click to expand...

"Better" is always debatable... Here is an example of a different approach:

Sub Main()
Dim s() As String = {"0324", "1234", "832"}
Dim hhmm As Integer

For Each s1 As String In s
hhmm = Integer.Parse(s1)

Dim h As Integer = hhmm \ 100
Dim m As Integer = hhmm Mod 100

Dim t As DateTime = DateTime.Today
t = t.AddHours(h).AddMinutes(m)
Console.WriteLine(t)
Next

Console.ReadKey()
End Sub
 
Thanks! This looks like a good approach. I can build a function
that will return the date with the time added and use that.
A question regarding your code. I noticed that you used
hhmm = Integer.Parse(s1)
Click to expand...

I typically use CInt(). Is there any advantage to using the
integer parse method or disadvantage to uing cint()? Thanks
Saga
 
Thanks! This looks like a good approach. I can build a function
that will return the date with the time added and use that.
A question regarding your code. I noticed that you used


I typically use CInt(). Is there any advantage to using the
integer parse method or disadvantage to uing cint()? Thanks
Saga
Click to expand...

Just a personal preference, I believe. That said, I wrote that reply
quickly, and the following way would be better:

if (Integer.TryParse(s1, hhmm)) then
' do the datetime stuff
end if

TryParse returns true if the value in the string can be parsed as an
integer. This would handle if the string "Noon" was passed in,
returning false, so that it is skipped.
 
I need to add the time a a date, specifically, the current date.
This seemed easy enough, but I found that thi wasn't so.

As in input I get 3 or 4 digits representing the date. Valid
input string are:

"0344", "1102", "456"

The minutes are always 2 digits, but the hour can be either
1 or 2 digits.

What I did was first come up with a function to normalize
the input string which formats it hh:mm:
Click to expand...

If you don't use a 24 hour clock here (HHmm), then your not ever going to be
able to distinguish between am and pm with out more information :). So, here
is what I have assuming 24 hour clock...

Option Explicit On
Option Strict On

Module Module1

Sub Main()
Dim str() As String = {"1146", "0344", "442", "601", "1302", "2359"}

Dim fmt As String = "MM/dd/yyyy HHmm"
For Each t As String In str
Dim cur As String = Date.Today.ToString("MM/dd/yyyy ") & String.Format("{0,4}", t).Replace(" ", "0")
Dim d As Date
Date.TryParseExact(cur, fmt, Nothing, Globalization.DateTimeStyles.None, d)
Console.WriteLine(d)
Next
End Sub

End Module
 
If you don't use a 24 hour clock here (HHmm), then your not ever going to be
able to distinguish between am and pm with out more information :). So, here
is what I have assuming 24 hour clock...

Option Explicit On
Option Strict On

Module Module1

Sub Main()
Dim str() As String = {"1146", "0344", "442", "601", "1302", "2359"}

Dim fmt As String = "MM/dd/yyyy HHmm"
For Each t As String In str
Dim cur As String = Date.Today.ToString("MM/dd/yyyy ") & String.Format("{0,4}", t).Replace(" ", "0")
Dim d As Date
Date.TryParseExact(cur, fmt, Nothing, Globalization.DateTimeStyles.None, d)
Console.WriteLine(d)
Next
End Sub

End Module
Click to expand...

Technically - you should be checking the return value of TryParseExact. It
returns a Boolean value indicating if it was able to succesfully parse the
string as a date or not :)
 
Thanks again. Saga

Family Tree Mike said:
Just a personal preference, I believe. That said, I wrote that reply
quickly, and the following way would be better:

if (Integer.TryParse(s1, hhmm)) then
' do the datetime stuff
end if

TryParse returns true if the value in the string can be parsed as an
integer. This would handle if the string "Noon" was passed in, returning
false, so that it is skipped.
Click to expand...
 
Thanks for your reply. You are correct in assuming that the
time data is in 24 hour format. Saga
 
Thanks for the addtional tip. In theory, all data has been
validated by the time it reaches this point, but I'll add this
extra validation step just to be on the safe side. Saga
 
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