How to delete table columns on 1-0 mask?

[rovnyart]

I have a 96-column table with strings. I also have 96-elemets int array (mask) with 1 and 0's.

What i want to do is to is to delete (or hide - but i've read that it's not possible) all the columns with index corresponding to 0 in mask array.

example: 

table columns

1 2 3 4 5

mask 

0 1 0 0 1

I want to delete columns 1, 3 and 4 and leave only 2 and 5 in my table.

How can i do that?

If i create for loop with i as index of the column, when i do DeleteTableColumns() columns count decreases, and i get an out-of range error:(

Or do i have a possibility to hide unneeded columns (not set their width to 1, it's very ugly-looking)?

Please help me(((

[Johannes_T · Accepted solution]

Hello rovnyart!

1. Removing table columns:

I suspect that the reason why you are getting the out-of-range error is due to the fact that in your for-loop, as you are deleting columns from the table, you'll eventually end up referencing a column that does no longer exist, because other columns before it have been deleted. While you are deleting each column at a time from your table in the for-loop, the column index number will shift, because you have deleted other columns before it.

In order to solve this, while you are deleting a column in your for-loop, make sure you also take into account that the column index is shifted because of removed columns.

2. Hiding table columns:

You can use the ATTR_COLUMN_VISIBLE attribute to hide table columns:

http://forums.ni.com/t5/LabWindows-CVI-Idea-Exchange/Add-ATTR-COLUMN-VISIBLE-attribute-for-table-col...

http://zone.ni.com/reference/en-XX/help/370051Y-01/cvi/uiref/cviattrcolumnvisible_column/

3. Alternatives:

Note that another alternative would also be to use a tree control instead, as the tree control also supports hidable columns:

http://forums.ni.com/t5/LabWindows-CVI/Table-Hide-Column/td-p/569773

Best regards!

- Johannes

[RobertoBozzolo]

---

1. Removing table columns:

I suspect that the reason why you are getting the out-of-range error is due to the fact that in your for-loop, as you are deleting columns from the table, you'll eventually end up referencing a column that does no longer exist, because other columns before it have been deleted. While you are deleting each column at a time from your table in the for-loop, the column index number will shift, because you have deleted other columns before it.

In order to solve this, while you are deleting a column in your for-loop, make sure you also take into account that the column index is shifted because of removed columns.

---

Or more simpler start deleting columns from the end of the table 

[rovnyart]

2. Hiding table columns:

You can use the ATTR_COLUMN_VISIBLE attribute to hide table columns:

That's not supported for tables, only for trees:(

[Wolfgang]

...this depends on the version of CVI. For trees this attribute is available since version 7, for tables since version 2012.

[rovnyart]

In order to solve this, while you are deleting a column in your for-loop, make sure you also take into account that the column index is shifted because of removed columns.

And how should i do that?=)

[Wolfgang]

for example having a loop index and a separate column index

[rovnyart]

thanks a lot, my friends!

I've updated to CVI 2012 and found, that ATTR_COLUMN_VISIBLE works on tables) Problem solved

[Johannes_T]

You are very welcome, rovnyart! You should also give credits to RobertoBozzolo, as his proposed solution for iterating over the control columns backwards is a lot simpler and straightforward, than the mechanism required to iterate over the columns from the beginning.

Best regards!

- Johannes