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Allocating memory to variable
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Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Versions des environnements
Visual FoxPro:
VFP 9 SP2
OS:
Windows XP SP2
Network:
Windows 2008 Server
Database:
MySQL
Divers
Thread ID:
01436706
Message ID:
01436713
Vues:
59
>>>Hello,
>>>
>>>I need to do the following:
>>>1) Query 100,000 lines from different tables and extract a string of about 200 characters per line,
>>>2) Add each line to a variable plus line break,
>>>3) Create a file (using StrToFile()) from the variable.
>>>
>>>I wonder how I can prevent performance problems by calling 100,000 times lcString = lcString + lcLine. This is going to re-allocate memory all the time, and I like to pre-allocate the needed memory for best performance. I remember having read an article about this many years ago (from Christopher) but I really do not remember anything about it, so I would be very thankful if somebody would give me a tip.
>>
>>Can you write to the file directly without using a variable and strtofile using fwrite function?
>
>I could but I would expect this to take even more time, because as the file grows it would have to move it around quite a lot?

For fast string manipulations see also an example in this message Re: Fast string function Thread #1358927 Message #1358936
If it's not broken, fix it until it is.


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