as nice as # inv is, you may find this adverb more flexible and intuitive:
insertitem =: 1 : '(u"_ {. ]) , [ , u"_ }. ]'
the adverb argument is a verb that tells which item position to insert. The
verb argument is dyadic, but can be a constant verb. Add @:] to it to just use
y as the argument To insert columns, you would transpose first, to make the
columns the items.
1 2: insertitem &.|: 3 3 $ 0
0 0 1 0
0 0 1 0
0 0 1 0
1 2 3 2: insertitem &.|: 3 3 $ 0
0 0 1 0
0 0 2 0
0 0 3 0
1 2: insertitem 1 2: insertitem &.|: 3 3 $ 0
0 0 1 0
0 0 1 0
1 1 1 1
0 0 1 0
deleteitem =: {. , >:@[ }. ] NB. verb
2 deleteitem 2 deleteitem &.|: 1 2: insertitem 1 2: insertitem &.|: 3 3 $ 0
0 0 0
0 0 0
0 0 0
----- Original Message -----
From: Sebastian <[email protected]>
To: "[email protected]" <[email protected]>
Cc:
Sent: Thursday, September 11, 2014 5:21 AM
Subject: [Jprogramming] Extend/reduce matrix dimensions
Hi,
I know the verbs , ,. ,: to add rows, columns and dimensions to
matrices. It is easy to add these to begin or the end of the
corrosponding dimension, but what is to do, if I want to add one
row/column in the middle of a matrix? Is the only way to slice the
matrix in two pieces and join them with the new row/column?
A few examples:
Initial situation:
3 3 $ 0
0 0 0
0 0 0
0 0 0
add column somewhere to the middle:
0 0 1 0
0 0 1 0
0 0 1 0
add row somewhere to the middle:
0 0 1 0
0 0 1 0
1 1 1 1
0 0 1 0
remove the added column:
0 0 0
0 0 0
1 1 1
0 0 0
and the row:
0 0 0
0 0 0
0 0 0
Can anyone help me with this?
Regards
Sebastian
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