Why Doesn't Mathematica Erase Memory Between Runs?

[Rjah]

Hi,

I ran this program:

P = Table[Subscript[p, i, j], {i, 0, 3}, {j, 0, 2}]
For[j = 0; i=0, j <= 2, j++, Subscript[p, i, j] = 2]
MatrixForm[P]

What is gives me is this:
2 2 2
p[1,0] p[1,1] p[1,2]
p[2,0] p[2,1] p[2,2]
p[3,0] p[3,1] p[3,2]


If I change the program and rerun it:

Clear[p]
P = Table[Subscript[p, i, j], {i, 0, 3}, {j, 0, 2}]
For[j = 0; i=1, j <= 2, j++, Subscript[p, i, j] = 2]
MatrixForm[P]

Now it gives me:

2 2 2
1 1 1
p[2,0] p[2,1] p[2,2]
p[3,0] p[3,1] p[3,2]


I was expecting something like:
p[0,0] p[0,1] p[0,2]
1 1 1
p[2,0] p[2,1] p[2,2]
p[3,0] p[3,1] p[3,2]


I want mathematica to erase its memory from the previous run, but nothing seems to work!


Any suggestions?

 

[CompuChip]

Did you try something like
Clear[P]
or
For[every {i, j}, Subscript[p, i, j] = .;]

 

[Dale]

You might try ClearAll or Remove instead of Clear.