Tell me I'm not crazy

Phil Davis revdev at pdslabs.net
Mon Sep 19 17:57:04 EDT 2011


On 9/19/11 1:48 PM, Tereza Snyder wrote:
> You CAN compare arrays for equality (see the docs for "="), but evidently not for INequality!

Right. You're not crazy. That's my experience too.
Phil
>
>
> On Sep 19, 2011, at 3:42 PM, Andre Garzia wrote:
>
>> Tereza,
>>
>> I don't think you can compare arrays like that... I never tried to do so, I
>> always sort the keys and iterate thru them.
>>
>> andre
>>
>> On Mon, Sep 19, 2011 at 5:30 PM, Tereza Snyder<tereza at califex.com>  wrote:
>>
>>> I recently encountered a problem implementing an undo function in a script.
>>> I needed to compare two arrays to see if any values had changed, like this:
>>>
>>> put (tArray1<>  tArray2) into sDirtyFlag
>>>
>>> so that sDirtyFlag would be true when the arrays failed to match. However,
>>> sDirtyFlag was always false! No matter what!
>>>
>>> I put the two arrays into globals and compared them in the message box,
>>> like this:
>>>
>>> put (gArray1 = gArray2), and the result was always correct. I thought there
>>> was some hidden horrible error in my script that dementia prevented me from
>>> seeing, until I realized that in my script I was using "<>" not "=" to
>>> compare.
>>>
>>> See if the following script, pasted into a button, mystifies you the way it
>>> did me. If you comment out the line:
>>>
>>> put "xx" into  tTestA2["low2"]
>>>
>>> so that the arrays ARE equal you might see, as I did, that the comparison
>>> is correct.
>>>
>>> Evidently in LiveCode 4.5.3, buildnumber 1444, on MacOS 10.6.8,
>>>
>>> "(tTestA1<>  tTestA2)" is not the same as "not(tTestA1 = tTestA2)" when the
>>> arrays are unequal.
>>>
>>> (I apologize that the example is so elaborate, I was attempting to
>>> reproduce the error environment.)
>>>
>>>
>>> tereza
>>>
>>> -- mind the linewraps
>>> ------------------------------
>>>
>>> on mouseUp
>>>    DoArrayComparison
>>> end mouseUp
>>>
>>> on DoArrayComparison
>>>    -- create 1 array
>>>    repeat for each item iii in "low1,low2,low3"
>>>        repeat for each item ii in "lower1,lower2,lower3"
>>>            repeat for each item i in "lowest1,lowest2,lowest3"
>>>                put "data"&&  iii&&  ii&&  i into tA1[iii][ii][i]
>>>            end repeat
>>>        end repeat
>>>    end repeat
>>>    -- create 2 arrays from it
>>>    put tA1 into tTestA1
>>>    put tTestA1 into tTestA2
>>>    -- make them unequal
>>>    put "xx" into  tTestA2["low2"]
>>>    -- do three comparisons
>>>    put "(tTestA1 = tTestA2)="&  (tTestA1 = tTestA2)&cr&  \
>>>            "(tTestA1<>  tTestA2)="&  (tTestA1<>  tTestA2)&cr&  \
>>>            "not(tTestA1 = tTestA2)="&  not(tTestA1 = tTestA2)
>>> end DoArrayComparison
>>>
>>> -------------------------------
>>>
>>> --
>>> Tereza Snyder
>>> Califex Software, Inc.
>>> <www.califexsoftware.com>
>>>
>>>
>>>
>>>
>>> _______________________________________________
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>>>
>>
>>
>> -- 
>> http://www.andregarzia.com All We Do Is Code.
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>
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-- 
Phil Davis

PDS Labs
Professional Software Development
http://pdslabs.net





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