strings become numbers and get in to the matrix

i have a matrice

[1 0 -1 -1 2 -1 1

1 0 -1 -1 2 -1 1

1 -1 0 -1 2 -1 1

1 0 -1 -1 2 -1 1];

and where the number is positive i need to replace ' i ' upon the ASCII is 105 , ( ' i ' its like increase )

where the number is negative i need to replace ' d ' upon the ASCII is 100 ( ' d ' its like decrease )

and where the number is 0 i need to replace ' s ' upon the ASCII is 115 ( ' s ' its like same )

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for example : if i have vector [ -1 , 0 , 1]

the new vector will be : [100 , 115 , 105 ]

Answer 1

[Star Strider]

Use logical indexing:

v = [ -1 , 0 , 1];
pos = v > 0
neg = v < 0
zro = v == 0

and then do the replacements.

See the documentation section on Matrix Indexing for an extended discussion.