AIstarter

Testing if variable is empty changed?!

10 posts in this topic

Hello,

I recently upgraded from 3.3.8.1 to 3.3.14.2 and noticed something that doesn't make sense to me:

I'm using a script to fetch records from an MSSQL Database. Some fields are empty (which is correct) and using 3.3.8.1 this works fine and sets $var2 to "something"

If ($var = "") Then
    $var2 = "something"
EndIf

After upgrading to 3.3.14.2 this doesn't work anymore. The String has a length of zero (which is the way I use now as a workaround)

If (StringLen($var) = 0) Then
    $var2 = "something"
EndIf

But I don't understand why this won't work anymore. Any Idea?

Thanks!

Share this post


Link to post
Share on other sites



Both work for me:

Local $var = ""

If (StringLen($var) = 0) Then
    MsgBox(0, 1, "Works")
EndIf

If ($var = "") Then
    MsgBox(0, 2, "Works")
EndIf

I think something is wrong in your code... did you check for script breaking changes?


AutoIt.4.Life Clubrooms - Life is like a Donut (secret key)

Spoiler

My contributions to the AutoIt Community

Some messages & Apologizes:

If I hurt you, Please accept my apologies, I never (regardless of the situation) mean to hurt anybody!!!

Also, I am very busy with my project so I will appear in the last row of the online list, if you want to contact me: Email@TheDcoder.xyz

Or you can have a nice chat with me in freenode, I use the same nick on freenode too!

3fHNZJ.gif

PLEASE JOIN ##AutoIt AND HELP THE IRC AUTOIT COMMUNITY!

Share this post


Link to post
Share on other sites

Yes I did. I didn't notice anyhting regarding my problem.

But declaring the var with "" as in your example should work in any case - since then it is indeed '""'. Even with a new script and just declaring Dim $var (without = "") works.

In my case it's part of an array that comes back from am MSSQL query. This returns NULL - and it seems that this was handled in a different way? I tested my code on an old 3.3.8.1 installation and the same code (without StringLen) works perfectly. Strange?!

Share this post


Link to post
Share on other sites

Try using:

String($var)

Before the if statement :)


AutoIt.4.Life Clubrooms - Life is like a Donut (secret key)

Spoiler

My contributions to the AutoIt Community

Some messages & Apologizes:

If I hurt you, Please accept my apologies, I never (regardless of the situation) mean to hurt anybody!!!

Also, I am very busy with my project so I will appear in the last row of the online list, if you want to contact me: Email@TheDcoder.xyz

Or you can have a nice chat with me in freenode, I use the same nick on freenode too!

3fHNZJ.gif

PLEASE JOIN ##AutoIt AND HELP THE IRC AUTOIT COMMUNITY!

Share this post


Link to post
Share on other sites

Indeed

$var = String($var)

works fine with = ""

Did I miss something in the changelog? Or was is just a guess? Anyway, thanks a lot - I'll do a bit of code-rework now back to = "" with the String statement :)

Share this post


Link to post
Share on other sites

My pleasure! :D


AutoIt.4.Life Clubrooms - Life is like a Donut (secret key)

Spoiler

My contributions to the AutoIt Community

Some messages & Apologizes:

If I hurt you, Please accept my apologies, I never (regardless of the situation) mean to hurt anybody!!!

Also, I am very busy with my project so I will appear in the last row of the online list, if you want to contact me: Email@TheDcoder.xyz

Or you can have a nice chat with me in freenode, I use the same nick on freenode too!

3fHNZJ.gif

PLEASE JOIN ##AutoIt AND HELP THE IRC AUTOIT COMMUNITY!

Share this post


Link to post
Share on other sites

#7 ·  Posted (edited)

Null.....

You get null from SQL. 

Edited by mLipok

Signature beginning:   Wondering who uses AutoIT and what it can be used for ?
* GHAPI UDF - modest begining - comunication with GitHub REST API *
ADO.au3 UDF     POP3.au3 UDF     XML.au3 UDF    How to use IE.au3  UDF with  AutoIt v3.3.14.x  for other useful stuff click the following button

Spoiler

Any of my own code posted anywhere on the forum is available for use by others without any restriction of any kind. 

My contribution (my own projects): * Debenu Quick PDF Library - UDF * Debenu PDF Viewer SDK - UDF * Acrobat Reader - ActiveX Viewer * UDF for PDFCreator v1.x.x * XZip - UDF * AppCompatFlags UDF * CrowdinAPI UDF * _WinMergeCompare2Files() * _JavaExceptionAdd() * _IsBeta() * Writing DPI Awareness App - workaround * _AutoIt_RequiredVersion() * Chilkatsoft.au3 UDF * TeamViewer.au3 UDF * JavaManagement UDF * VIES over SOAP * WinSCP UDF * GHAPI UDF - modest begining - comunication with GitHub REST API *

My contribution to others projects or UDF based on  others projects: * _sql.au3 UDF  * POP3.au3 UDF *  RTF Printer - UDF * XML.au3 - BETA * ADO.au3 UDF SMTP Mailer UDF *

Useful links: * Forum Rules * Forum etiquette *  Forum Information and FAQs * How to post code on the forum * AutoIt Online Documentation * AutoIt Online Beta Documentation * SciTE4AutoIt3 getting started * Convert text blocks to AutoIt code * Games made in Autoit * Programming related sites * Polish AutoIt Tutorial * DllCall Code Generator * 

Wiki: Expand your knowledge - AutoIt Wiki * Collection of User Defined Functions * How to use HelpFile * Best coding practices * 

IE Related:  * How to use IE.au3  UDF with  AutoIt v3.3.14.x * Why isn't Autoit able to click a Javascript Dialog? * Clicking javascript button with no ID * IE document >> save as MHT file * IETab Switcher (by LarsJ ) * HTML Entities * _IEquerySelectorAll() (by uncommon) * 

I encourage you to read: * Global Vars * Best Coding Practices * Please explain code used in Help file for several File functions * OOP-like approach in AutoIt * UDF-Spec Questions *  EXAMPLE: How To Catch ConsoleWrite() output to a file or to CMD *

"Homo sum; humani nil a me alienum puto" - Publius Terentius Afer
"Program are meant to be read by humans and only incidentally for computers and execute" - Donald Knuth, "The Art of Computer Programming"
:naughty:  :ranting:, be  :) and       \\//_.

Anticipating Errors :  "Any program that accepts data from a user must include code to validate that data before sending it to the data store. You cannot rely on the data store, ...., or even your programming language to notify you of problems. You must check every byte entered by your users, making sure that data is the correct type for its field and that required fields are not empty."

Signature last update: 2017-06-04

Share this post


Link to post
Share on other sites
35 minutes ago, mLipok said:

Null.....

You get null from SQL. 

Yes, I get null from SQL - that didn't change between AutoIT Versions and is still the same. But testing for null did change as it seems. In 3.3.8.1. a test for null works fine with just = "" - apparently this changed in new versions where you have to take a look at StringLen or String($var). That was my problem...

Share this post


Link to post
Share on other sites
16 minutes ago, AIstarter said:

But testing for null did change as it seems. In 3.3.8.1. a test for null works fine with just = "" - apparently this changed in new versions where you have to take a look at StringLen or String($var). That was my problem...

 

https://www.autoitscript.com/autoit3/docs/autoit_changelog.txt
3.3.10.0 (23rd December, 2013) (Release)
Added: Keyword Null.
 

You should check like this:
 

If $var = Null or $var = "" then
...
EndIf

 


Signature beginning:   Wondering who uses AutoIT and what it can be used for ?
* GHAPI UDF - modest begining - comunication with GitHub REST API *
ADO.au3 UDF     POP3.au3 UDF     XML.au3 UDF    How to use IE.au3  UDF with  AutoIt v3.3.14.x  for other useful stuff click the following button

Spoiler

Any of my own code posted anywhere on the forum is available for use by others without any restriction of any kind. 

My contribution (my own projects): * Debenu Quick PDF Library - UDF * Debenu PDF Viewer SDK - UDF * Acrobat Reader - ActiveX Viewer * UDF for PDFCreator v1.x.x * XZip - UDF * AppCompatFlags UDF * CrowdinAPI UDF * _WinMergeCompare2Files() * _JavaExceptionAdd() * _IsBeta() * Writing DPI Awareness App - workaround * _AutoIt_RequiredVersion() * Chilkatsoft.au3 UDF * TeamViewer.au3 UDF * JavaManagement UDF * VIES over SOAP * WinSCP UDF * GHAPI UDF - modest begining - comunication with GitHub REST API *

My contribution to others projects or UDF based on  others projects: * _sql.au3 UDF  * POP3.au3 UDF *  RTF Printer - UDF * XML.au3 - BETA * ADO.au3 UDF SMTP Mailer UDF *

Useful links: * Forum Rules * Forum etiquette *  Forum Information and FAQs * How to post code on the forum * AutoIt Online Documentation * AutoIt Online Beta Documentation * SciTE4AutoIt3 getting started * Convert text blocks to AutoIt code * Games made in Autoit * Programming related sites * Polish AutoIt Tutorial * DllCall Code Generator * 

Wiki: Expand your knowledge - AutoIt Wiki * Collection of User Defined Functions * How to use HelpFile * Best coding practices * 

IE Related:  * How to use IE.au3  UDF with  AutoIt v3.3.14.x * Why isn't Autoit able to click a Javascript Dialog? * Clicking javascript button with no ID * IE document >> save as MHT file * IETab Switcher (by LarsJ ) * HTML Entities * _IEquerySelectorAll() (by uncommon) * 

I encourage you to read: * Global Vars * Best Coding Practices * Please explain code used in Help file for several File functions * OOP-like approach in AutoIt * UDF-Spec Questions *  EXAMPLE: How To Catch ConsoleWrite() output to a file or to CMD *

"Homo sum; humani nil a me alienum puto" - Publius Terentius Afer
"Program are meant to be read by humans and only incidentally for computers and execute" - Donald Knuth, "The Art of Computer Programming"
:naughty:  :ranting:, be  :) and       \\//_.

Anticipating Errors :  "Any program that accepts data from a user must include code to validate that data before sending it to the data store. You cannot rely on the data store, ...., or even your programming language to notify you of problems. You must check every byte entered by your users, making sure that data is the correct type for its field and that required fields are not empty."

Signature last update: 2017-06-04

Share this post


Link to post
Share on other sites

Thanks @mLipok - i did read the changelog but didn't quite register what keyword meant. Checking for Null works of course.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now