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Using == vs =
Message
De
06/11/2015 04:56:01
 
 
À
06/11/2015 03:22:29
Walter Meester
HoogkarspelPays-Bas
Information générale
Forum:
Visual FoxPro
Catégorie:
Autre
Titre:
Versions des environnements
Visual FoxPro:
VFP 9 SP2
OS:
Windows 10
Network:
Windows 2008 Server
Database:
MS SQL Server
Application:
Web
Divers
Thread ID:
01627149
Message ID:
01627158
Vues:
68
>Just encountered a bug in our software releated to the use of = when set exact is set to off.
>
>I Know I should be using == in those cases where comparing strings of different lenght, but just a small test made me wonder.
>
>Is there any reason I should not use == for any comparison in VFP? It seems to work for any datatype.
>
>Is there any gotcha using == as a standard?
>
>
>Walter,

Hi Walter:

- When you want to make sure you compare the exact match, then you should use "==" to make the comparison independent of the SET EXACT setting
- When you want to compare by the alternative logic of "begins with", then you use "=" and SET EXACT OFF

In regards of the velocity of comparison between "==" and "=", in my PC a 1000000 (millon) FOR loop shows me that "== is a little faster, but negligible in small loops:
*--
nSecs=SECONDS()
FOR I = 1 TO 1000000
   =("AA" = "AAA")
ENDFOR
? SECONDS()-nSecs

0.187

*--
nSecs=SECONDS()
FOR I = 1 TO 1000000
   =("AA" == "AAA")
ENDFOR
? SECONDS()-nSecs

0.140

*--
Regards.-
Fernando D. Bozzo
Madrid / Spain
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