IS this by design?

[MattHiggs]

Hello all.  I have noticed that the Int conversion function behaves in a manner that I would not expect to be by design, and I wanted to confirm if it was, in fact, by design.  Lets consider the below line of code:

Int ("This is not an integer")

Now, in other scripting languages, like powershell, if you try converting a string like the one above into an integer, it throws an error:

I would expect autoit would behave in a similar way.  However, when you run the sample at the beginning of the post, it does not return an error.  It actually successfully returns the integer 0, which is a very odd behavior, since that would seem to indicate that the integers Int ("0" ) and Int ("Any string which is not an integer" ) are equal and valid.  Consider the below script, in which I used Mediainfo.dll to return the properties associated with a media file on my computer.  To make it more easy to follow along, the contents of the $array variable will be displayed underneath the code snippet:

For $i = 0 To UBound ( $Array ) - 1 Step 1
    $split = StringSplit ( StringStripWS ( $Array[$i], 8 ), ":", 2 ) ;We try to split each line using ":" as the delimeter
    If @error Then ;set error variable to 0 and continueloop if split fails
        SetError ( 0 )
        ContinueLoop
    EndIf
    If StringLeft ( $split[0], 5 ) = "Width" And IsInt ( Int ( $split[1] ) ) Then ;looking for the line "Width:1208" (spaces removed for convenience) in the array/text file
        $width = $split[1]
    EndIf
    If StringLeft ( $split[0], 6 ) = "Height" And IsInt ( Int ( $split[1] ) ) Then ;looking for the line "Height:807" (spaces removed for convenience) in the array/text file
        $height = $split[1]
    EndIf

Next

The contents of $array varialbe:

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Complete name                            : C:\Users\whiggs\Pictures\2018-03-22 15_00_45-ASUS Wireless Router RT-AC1750 - Network Map.png

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Unfortunately, Autoit reads in the text as a string, so trying to use IsInt ($split[1]) fails to identify the value "1208" as an int when passed the line containing the text we are looking for because it is a string in this context.  So, my first thought as to how to solve this would be to attempt to convert the string into an integer before passing it to "isInt ()", and use error handling to handle instances where an actual string is passed to Int().  However, that logic does not work with autoit because the Int() conversion function, even when passed what should be invalid parameter, still returns a variable as if it had processed successfully: 0.  0 is an int, and "0" does not equal "This is not an integer".  It just seems really odd that Autoit's Int() conversion function takes what should be and invalid parameter entry and returns a valid integer value.  Just to be clear here, I am not asking for help.  I already was able to work around this using regular expressions instead.  I am simply asking if this kind of behavior in Autoit is by design.  That is all.

 

Edited April 25, 2020 by MattHiggs

[Jos]

A bit of a long story to ask about the int() & IsInt() functions.
AutoIt3's Int() function converts the expression found into a integer, and doesn't cast like I assume your screen capture example does.
Int("whatever string") will result in an integer value containing 0 , so IsInt(Int("whatever string") )  obviously will always be true!
You need to test the original expression with IsInt() to get a result you want. So in simple script form:

Dim $split[2] = [1, "test"]
ConsoleWrite("$split[1]=" & $split[1] & @CRLF)
ConsoleWrite("Int($split[1])=" & Int($split[1]) & @CRLF)
ConsoleWrite("incorrect test IsInt(Int($split[1]))=" & IsInt(Int($split[1])) & @CRLF)
ConsoleWrite("correct test   IsInt($split[1])=" & IsInt($split[1]) & @CRLF)

Jos

 

Edited April 25, 2020 by Jos

[TheDcoder]

@Jos Your logic is right, but I think OP is wanting to know why Int doesn't have a error-checking mechanism to detect non-numeric input.

@MattHiggs It does look like this function works this way by design, I do agree that it would be nice to have some error-checking mechanism, the best way to implement it would be to set @error in case the input is not numeric, this is backward compatible with existing code

I guess this is something I can implement in my cross-platform implementation

Edited April 25, 2020 by TheDcoder

[Jos]

2 minutes ago, TheDcoder said:

@Jos Your logic is right, but I think OP is wanting to know why Int doesn't have a error-checking mechanism to detect non-numeric input.

I don't understand that question. It simply converts any none numeric to 0 as AutoIt3 always does without setting any @error flag.

Edited April 25, 2020 by Jos

[TheDcoder]

2 minutes ago, Jos said:

I don't understand that question.

I think you are mis-understanding the question, OP is aware of how the function works, but he wants to know why it was designed to work that way.

[Jos]

Ah ok ...  Design choices is one Jon would have to answer.   

Jos

[Jos]

This could be an approach to test a variable whether it contains an INT, either as number or string:

_TestInt("1028")
_TestInt(1028)
_TestInt(1028.5)
_TestInt("1028.5")
_TestInt("test")

Func _TestInt($istr)
    If _IsInt($istr) Then
        ConsoleWrite($istr & " is INT" & @CRLF)
    Else
        ConsoleWrite($istr & " is not an INT" & @CRLF)
    EndIf
EndFunc

; Test whether the variable contains an INT value either as string of number
Func _IsInt($istr)
    Return $istr == Int($istr)
EndFunc   ;==>_IsInt

Jos

Edited April 25, 2020 by Jos

[FrancescoDiMuro]

@MattHiggs
As Jos suggested, you could build your own "IsInt" function, like the following one:

#include <StringConstants.au3>

Global $blnReturnValue

$blnReturnValue = (_IsInt(10)     = 1 ? ConsoleWrite("Is Integer!" & @CRLF) : ConsoleWrite("Is NOT an Integer! Error: " & @error & @CRLF))
$blnReturnValue = (_IsInt(+15)    = 1 ? ConsoleWrite("Is Integer!" & @CRLF) : ConsoleWrite("Is NOT an Integer! Error: " & @error & @CRLF))
$blnReturnValue = (_IsInt(-20)    = 1 ? ConsoleWrite("Is Integer!" & @CRLF) : ConsoleWrite("Is NOT an Integer! Error: " & @error & @CRLF))
$blnReturnValue = (_IsInt("ABCD") = 1 ? ConsoleWrite("Is Integer!" & @CRLF) : ConsoleWrite("Is NOT an Integer! Error: " & @error & @CRLF))
$blnReturnValue = (_IsInt(150.2)  = 1 ? ConsoleWrite("Is Integer!" & @CRLF) : ConsoleWrite("Is NOT an Integer! Error: " & @error & @CRLF))
$blnReturnValue = (_IsInt(-19.0)  = 1 ? ConsoleWrite("Is Integer!" & @CRLF) : ConsoleWrite("Is NOT an Integer! Error: " & @error & @CRLF))
$blnReturnValue = (_IsInt(2430)   = 1 ? ConsoleWrite("Is Integer!" & @CRLF) : ConsoleWrite("Is NOT an Integer! Error: " & @error & @CRLF))
$blnReturnValue = (_IsInt("")     = 1 ? ConsoleWrite("Is Integer!" & @CRLF) : ConsoleWrite("Is NOT an Integer! Error: " & @error & @CRLF))


Func _IsInt($varUserInput)
    Return (StringRegExp($varUserInput, '^(?:[-+])?\d+(?:\.0)?$', $STR_REGEXPMATCH) = True ? SetError(0, 0, 1) : SetError(-1, 0, 0))
EndFunc

Edited April 25, 2020 by FrancescoDiMuro

[TheDcoder]

@Jos Nice! I was thinking if it was possible to write an UDF without using manual checking or RegEx but did not think of comparing the string with the number

@FrancescoDiMuro He is already using RegEx according to his first post.

[FrancescoDiMuro]

@TheDcoder
Read now 

[TheDcoder]

@FrancescoDiMuro I only wanted to point out that OP was already using regex, but thanks for sharing the RegEx version

[FrancescoDiMuro]

@TheDcoder
Sure, it is fun to have these challenges to solve with "one-line" instructions

[jchd]

Ahem! ... An integer may be signed and "1.0" is converted to an integer (not a double).

So back to drawing board for both == and regex guys!

[Jos]

6 minutes ago, jchd said:

Ahem! ... An integer may be signed and "1.0" is converted to an integer (not a double).

The sign I agree that the + needs to be removed in the string before compare, but the "1.0" should be _IsInt("1.0") = False ...right?

Jos  

[Musashi]

1 hour ago, Jos said:

Design choices is one Jon would have to answer.

This is probably neither the right place nor the right time (if it even exists) to ask this blasphemous question, but is @Jon  really the only one who can make adjustments (at least minor ones)  in the AutoIt core? 

[jchd]

Local $aInts =["1", "1.00", "1e0", "1e2", "1e-0", "1e+2", "1000000000000000000000000000000000000000000", "1000000000000000000000000000000000000000000.0", "1e120"]

For $s In $aInts
    ConsoleWrite($s & @TAB & IsInt(Number($s)) & @TAB & VarGetType(Number($s)) & @TAB & Number($s) & @LF)
    ConsoleWrite("+" & $s & @TAB & IsInt(Number($s)) & @TAB & VarGetType(Number($s)) & @TAB & Number("+" & $s) & @LF)
    ConsoleWrite("-" & $s & @TAB & IsInt(Number($s)) & @TAB & VarGetType(Number($s)) & @TAB & Number("-" & $s) & @LF)
Next

; That's the unnoticed bug AFAIK
ConsoleWrite(Number("12345678901234567890") & @LF)

More surprises when you look closer!

Edited April 25, 2020 by jchd
Sorry for so many edits!

[Jos]

Just trying to understand what you are showing with this example:
What is the difference between the last 2 consolewrite's other than then the starting character? 

 

[jchd]

This shows all the forms that a string can check the IsInt() test. Note the changed version and the underlying bugs in some conversions.

I just realized that "1E3" is not recognized as an integer FP value while "1e3" is.

Edited April 25, 2020 by jchd

[jchd]

Last test version with fixed version of Number()

Local $aInts =["", "1", "00001", "1.00", "1e0", "001.e0", "1e-0", "1e2", "1.0e+2", "9223372036854775807", "9223372036854775808", "10000000000000000000", "1000000000000000000.0", "1e120"]

For $s In $aInts
    ConsoleWrite($s & @TAB & IsInt(Number($s)) & @TAB & VarGetType(Number($s)) & @TAB & Number($s) & @TAB & "==>" & @TAB & VarGetType(_Number($s)) & @TAB & _Number($s) & @LF)
    ConsoleWrite("+" & $s & @TAB & IsInt(Number($s)) & @TAB & VarGetType(Number($s)) & @TAB & Number("+" & $s) & @TAB & "==>" & @TAB & VarGetType(_Number("+" & $s)) & @TAB & _Number("+" & $s) & @LF)
    ConsoleWrite("-" & $s & @TAB & IsInt(Number($s)) & @TAB & VarGetType(Number($s)) & @TAB & Number("-" & $s) & @TAB & "==>" & @TAB & VarGetType(_Number("-" & $s)) & @TAB & _Number("-" & $s) & @LF & @LF)
Next

; That's the unnoticed bug AFAIK
ConsoleWrite("33333333333333333333 gets erroneously converted to MaxInt64 = " & Number("33333333333333333333") & @LF & @LF)

; fixed version of Number()
Func _Number($s)
    Local $a = StringRegExp($s, "^([-+]?)0*(\d+)$", 1)
    If Not @error Then
        Local $l = StringLen($a[1])
        ; in case the int is oversized
        If $l > 19 Or ($a[0] <> "-" And $a[1] > "9223372036854775807") Or ($a[0] = "-" And $a[1] > "9223372036854775808") Then Return Number($s & ".0")
    EndIf
    Return Number($s)
EndFunc

Again sorry for multiple edits but I kept discovering missing cases.

I regard the current behavior of Number($s) as buggy when it silently converts input outside the Int64 range to MaxInt64 or MinInt64.

Also the exemple in help is missing the minus sign:

Local $dNumber13 = Number("-30") ; Returns 30

 

[MattHiggs]

Thanks for all the comments, guys.  I did not expect this much discussion on the matter.  Lol.  So, short answer is that, yes, it is by design.  That is all I needed to know.  Thanks!!

Edited April 27, 2020 by MattHiggs