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The trouble with Var's - 10/29/2008 1:09:55 AM

Bongman

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Joined: 10/18/2008
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Hi all

Im trying to write a script, that checks if a variable has decimal points or not.
I then want to include an if statement on this check.

However, whenever I perform arithmatic commands on these integers, they change to "Double" not Decimal as expected. Then, even if the var is changed so it has no decimal points (Ie a round number) it still remains a "double" not an "Integer" as expected.

here is the (quite unfinished) code:

Some help on this would be great :)

Cheers

Bongman

Post #: 1

RE: The trouble with Var's - 10/29/2008 1:26:22 AM

ebgreen

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This is one of the criticisms of dynamically typed languages. You rely on the interpreter to make typing decisions. If you don't like the typing decisions that it is making, use explicit type casting (CDbl, CInt, etc).

_____________________________

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(in reply to Bongman)

Post #: 2

RE: The trouble with Var's - 10/29/2008 1:40:12 AM

ebgreen

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In your code, the variables (r1,r2,r3,r4) will never have a typename of integer since they will always have a decimal component.

_____________________________

"... when you are good and crazy, oooh, oooh, oooh, the sky is the limit!" - The Tick
Goog places to start:http://www.visualbasicscript.com/m_24727/tm.htm
http://www.visualbasicscript.com/m_47117/tm.htm

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Post #: 3

RE: The trouble with Var's - 10/29/2008 1:49:43 AM

Bongman

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Hi Ebgreen

typename(r1) returns "double" for r1,r2,r3 &,r4 which is a "64-bit floating point" number.

I expected either Integer or Decimal.

Can you think of any other way of doing this? Prehaps converting the Double back to integer, or prehaps "long"?

All I want to do is determine if the result is a whole number or not.

Regards

Bongman

(in reply to ebgreen)

Post #: 4

RE: The trouble with Var's - 10/29/2008 1:54:32 AM

ebgreen

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What do you mean by result? The result variable is always a whole number in your code.

_____________________________

"... when you are good and crazy, oooh, oooh, oooh, the sky is the limit!" - The Tick
Goog places to start:http://www.visualbasicscript.com/m_24727/tm.htm
http://www.visualbasicscript.com/m_47117/tm.htm

(in reply to Bongman)

Post #: 5

RE: The trouble with Var's - 10/29/2008 2:14:31 AM

Bongman

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Sorry, I shouldn't have referred to it as "result"

I meant r1,r2,r3 & r4.

I want to record (echo or add a line in a text file) "result" when r1,r2,r3 & r4 all return a whole number.

Regards

Bongman

(in reply to ebgreen)

Post #: 6

RE: The trouble with Var's - 10/29/2008 2:25:07 AM

ebgreen

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Try this, but be forewarned that Ints can't be very large.

_____________________________

"... when you are good and crazy, oooh, oooh, oooh, the sky is the limit!" - The Tick
Goog places to start:http://www.visualbasicscript.com/m_24727/tm.htm
http://www.visualbasicscript.com/m_47117/tm.htm

(in reply to Bongman)

Post #: 7

RE: The trouble with Var's - 10/29/2008 2:29:12 AM

ehvbs

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If CInt() - conversion to Integer - fails because of the data range or problems with rounding,
use Fix() - truncation of fractional part.

(in reply to ebgreen)

Post #: 8

RE: The trouble with Var's - 10/29/2008 2:41:17 AM

ebgreen

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Good advice.

_____________________________

"... when you are good and crazy, oooh, oooh, oooh, the sky is the limit!" - The Tick
Goog places to start:http://www.visualbasicscript.com/m_24727/tm.htm
http://www.visualbasicscript.com/m_47117/tm.htm

(in reply to ehvbs)

Post #: 9

RE: The trouble with Var's - 10/29/2008 12:51:33 PM

TNO

Posts: 1402
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why not convert to a string and check for the existence of the decimal point?

_____________________________

To iterate is human, to recurse divine. -- L. Peter Deutsch

(in reply to ebgreen)

Post #: 10

RE: The trouble with Var's - 10/29/2008 5:58:10 PM

ehvbs

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Because being a whole number or not is a mathematical not a philological question.

(in reply to TNO)

Post #: 11

RE: The trouble with Var's - 10/29/2008 10:56:19 PM

TNO

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In this case its not even a mathematical one, its whether the decimal exists or not, ignoring whole numbers.

So..., why not this and use the type coercion to our advantage?

_____________________________

To iterate is human, to recurse divine. -- L. Peter Deutsch

(in reply to ehvbs)

Post #: 12

RE: The trouble with Var's - 10/30/2008 12:43:59 AM

ebgreen

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I debated that as a way to do the IsWholeNumber function. At the time I couldn't remember how something like this would be represented as a string:

nNum = 3
nDiv = 100
nFac = 1000

dblTemp = nNum/nDiv
WScript.Echo CStr(dblTemp*1000)

I couldn't remember if that would represent the string as 30 or 30.00. I did some testing and it does 30. SO looking for the decimal should work just fine.

_____________________________

"... when you are good and crazy, oooh, oooh, oooh, the sky is the limit!" - The Tick
Goog places to start:http://www.visualbasicscript.com/m_24727/tm.htm
http://www.visualbasicscript.com/m_47117/tm.htm

(in reply to TNO)

Post #: 13

RE: The trouble with Var's - 10/30/2008 2:00:43 AM

ehvbs

Posts: 2224
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From: Germany
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Don't rely on CStr() or other formatting/conversion:

Dim aTests : aTests = Array( _
      Array( 3.99       , ".", "P fails for DE because of wrong DP"  ) _
    , Array( 3.99       , ",", "P succeeds for DE, will fail for EN" ) _
    , Array( 4.00       , ",", "easy case" ) _
    , Array( 1E+15 - 1  , ",", "last number CStr() displays in human format" ) _
    , Array( 1E+15      , ",", "CStr() starts scientific format; P is lucky" ) _
    , Array( 1E+15 + 100, ",", "CStr() uses scientific format; P is out of luck" ) _
    , Array( 1E+15 + 0.9, ",", "M still ok, P is fooled by CStr(), mark the loss of precision" ) _
                            )
 Dim nCnt : nCnt = 0
 Dim aTest
 For Each aTest In aTests
     WScript.Echo "--------", nCnt, aTest( 2 )
     WScript.Echo "CStr():      ", CStr( aTest( 0 ) )
     WScript.Echo "FormatNumber:", FormatNumber( aTest( 0 ), 6, , , False )
     WScript.Echo "Philology:   ", CStr( IsWholeNumP( aTest( 0 ), aTest( 1 ) ) )
     WScript.Echo "Mathematics: ", CStr( IsWholeNumM( aTest( 0 ) ) )
     WScript.Echo "Diff:        ", aTest( 0 ) - Fix( aTest( 0 ) )

nCnt = nCnt + 1
 Next

Function IsWholeNumP( nNum, sDP )
 IsWholeNumP = 0 = InStr( CStr( nNum ), sDP )
End Function

Function IsWholeNumM( nNum )
 IsWholeNumM = nNum = Fix( nNum )
End Function

output (DE locale):

=== WholeNumber: whole number test (TNO) ===================================
-------- 0 P fails for DE because of wrong DP
CStr():       3,99
FormatNumber: 3,990000
Philology:    Wahr
Mathematics:  Falsch
Diff:         0,99
-------- 1 P succeeds for DE, will fail for EN
CStr():       3,99
FormatNumber: 3,990000
Philology:    Falsch
Mathematics:  Falsch
Diff:         0,99
-------- 2 easy case
CStr():       4
FormatNumber: 4,000000
Philology:    Wahr
Mathematics:  Wahr
Diff:         0
-------- 3 last number CStr() displays in human format
CStr():       999999999999999
FormatNumber: 999999999999999,000000
Philology:    Wahr
Mathematics:  Wahr
Diff:         0
-------- 4 CStr() starts scientific format; P is lucky
CStr():       1E+15
FormatNumber: 1000000000000000,000000
Philology:    Wahr
Mathematics:  Wahr
Diff:         0
-------- 5 CStr() uses scientific format; P is out of luck
CStr():       1,0000000000001E+15
FormatNumber: 1000000000000100,000000
Philology:    Falsch
Mathematics:  Wahr
Diff:         0
-------- 6 M still ok, P is fooled by CStr(), mark the loss of precision
CStr():       1E+15
FormatNumber: 1000000000000000,000000
Philology:    Wahr
Mathematics:  Falsch
Diff:         0,875
=== WholeNumber: 0 done (00:00:00) =========================================

Math alone is evil enough, don't give Philology a chance to make things worse.

(in reply to ebgreen)

Post #: 14

RE: The trouble with Var's - 10/30/2008 3:56:00 AM

TNO

Posts: 1402
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From: thenewobjective.com
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The OP's question was generic and simple and a generic and simple solution was provided. Nothing was asked about international formatting, nor issues regarding E notation, both of which are generally rare situations. At any rate he did not ask if it was a whole number, he asked if it contained a decimal point or not. If E notation is given, then an E notation number does not contain a decimal which is "correct", the same goes with the international number format. He didn't ask for the separator, he literally asked for the decimal point. Of course I could also ask if
3.00 should pass or fail this test (if precision has to be maintained), but regardless these issues were not brought up so a solution was not given. I didn't assume what he meant I offered a solution to the literal question

_____________________________

To iterate is human, to recurse divine. -- L. Peter Deutsch

(in reply to ehvbs)

Post #: 15

RE: The trouble with Var's - 10/30/2008 4:55:13 AM

ehvbs

Posts: 2224
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From: Germany
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Hi TNO,

having problems to understand your contribution, I'd like to ask: Do you propose to
use "number to string conversion" and "examinating the result for a certain character"
to determine whether the number has/contains a fractional part or not?

Regards

ehvbs

(in reply to TNO)

Post #: 16

RE: The trouble with Var's - 10/30/2008 5:10:15 AM

TNO

Posts: 1402
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From: thenewobjective.com
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With the current information given by the OP, yes that is the proposal I offer since it solves the problem given with the least amount of code. I was not seeking a grand solution for what seems to me to be a domain specific problem

_____________________________

To iterate is human, to recurse divine. -- L. Peter Deutsch

(in reply to ehvbs)

Post #: 17

RE: The trouble with Var's - 10/30/2008 5:25:59 AM

ehvbs

Posts: 2224
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Joined: 6/22/2005
From: Germany
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(1) How would you the define the domain for which your IsWholeNumber( <SomeNumber> ) function will
     give correct answers?

(2) Please show such a function which has less code than
     Function IsWholeNumM( nNum )
IsWholeNumM = nNum = Fix( nNum )
   End Function

(in reply to TNO)

Post #: 18

RE: The trouble with Var's - 10/30/2008 5:50:50 AM

TNO

Posts: 1402
Score: 16
Joined: 12/18/2004
From: thenewobjective.com
Status: offline

You're giving me a loaded question. As I just said I was not solving the problem of whole number vs not whole number, I was solving the existence of the decimal point or not, which provides the same solution to the OP's problem given.

So in the context of that,

#1 - The OP's examples define the domain
#2 - (based on the premise I just gave): InStr(CStr(Foo),".") = 0

_____________________________

To iterate is human, to recurse divine. -- L. Peter Deutsch

(in reply to ehvbs)

Post #: 19

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