best way to Dim arrays you don't know the size of?

  • Thread starter Thread starter Scott M
  • Start date Start date
S

Scott M

If you don't know the size of an array when you create it (and it
needs to be available to the whole program), is it more efficient to
use redim or (,) e.g. :

1.

Public class form1
….
Dim SampleArray(,) as string
…

Private sub Something()
Dim NowWeKnowTheValueOfTheArray as integer = 100
Dim NowWeKnowTheValueOfTheArray2 as integer = 1000

For i = 0 to NowWeKnowTheValueOfTheArray - 1
For j = 0 to NowWeKnowTheValueOfTheArray2 - 1
SampleArray(i, j) = "Something"
next
Next

Or

2.

Public class form1
…..
Dim SampleArray(0,1) as string
…..

Private sub Something()
Dim NowWeKnowTheValueOfTheArray as integer = 100
Dim NowWeKnowTheValueOfTheArray2 as integer = 1000

Redim SampleArray(NowWeKnowTheValueOfTheArray - 1 ,
NowWeKnowTheValueOfTheArray2 - 1)

For i = 0 to NowWeKnowTheValueOfTheArray - 1
For j = 0 to NowWeKnowTheValueOfTheArray2 - 1
SampleArray(i, j) = "Something"
next
Next

Or something else?
 
Scott M said:
If you don't know the size of an array when you create it (and it
needs to be available to the whole program), is it more efficient
to use redim or (,) e.g. :

1.

Public class form1
….
Dim SampleArray(,) as string
…

Private sub Something()
Dim NowWeKnowTheValueOfTheArray as integer = 100
Dim NowWeKnowTheValueOfTheArray2 as integer = 1000

For i = 0 to NowWeKnowTheValueOfTheArray - 1
For j = 0 to NowWeKnowTheValueOfTheArray2 - 1
SampleArray(i, j) = "Something"
next
Next

Or

2.

Public class form1
…..
Dim SampleArray(0,1) as string
…..

Private sub Something()
Dim NowWeKnowTheValueOfTheArray as integer = 100
Dim NowWeKnowTheValueOfTheArray2 as integer = 1000

Redim SampleArray(NowWeKnowTheValueOfTheArray - 1 ,
NowWeKnowTheValueOfTheArray2 - 1)

For i = 0 to NowWeKnowTheValueOfTheArray - 1
For j = 0 to NowWeKnowTheValueOfTheArray2 - 1
SampleArray(i, j) = "Something"
next
Next

Or something else?
Click to expand...


Use Dim to specify the dimension (rank) of the array (2-dimensional in this
case) only. Use Redim to create the array:

…..
Dim SampleArray(,) as string
…..

Private sub Something()
Dim NowWeKnowTheValueOfTheArray as integer = 100
Dim NowWeKnowTheValueOfTheArray2 as integer = 1000

Redim SampleArray(NowWeKnowTheValueOfTheArray - 1 ,
NowWeKnowTheValueOfTheArray2 - 1)

For i = 0 to NowWeKnowTheValueOfTheArray - 1
For j = 0 to NowWeKnowTheValueOfTheArray2 - 1
SampleArray(i, j) = "Something"
next
Next


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Armin

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