How can I make a function that creates a particular size 2D matrix that determines True or False if a random value between 0 and 1 is at or below a certain number? Below is what I have written but when I put in values all I get is a column of trues.
initializeGrid[rows_Integer, columns_Integer, value_] :=
Module[{table, booleanTable},
table = Table[RandomReal[], {r, rows}, {c, columns}];
booleanTable = BooleanTable[x <= value, table];
Return[booleanTable]
]
SeedRandom[123]
ran = RandomReal[1, {5, 5}];
PaddedForm[TableForm[ran], {3, 2}]
Replace all numbers below n with False or True otherwise
n = 0.6;
Unitize @ Threshold[ran, n] /. {1 :> True, 0 :> False} // TableForm
There are many ways to get a matrix of True and False:
Table[RandomReal[] < 0.2, {i, 10}, {j, 10}]
Change the 0.2 to your desired threshold and the 10 to your desired matrix size.
Or use RandomChoice to directly choose between True and False with a given probability:
RandomChoice[{0.8, 0.2} -> {True, False}, {10, 10}]
You can use the BoolEval package.
Needs["BoolEval`"]
matrix = RandomReal[1, {3, 3}]
(* Out: {{0.965037, 0.544295, 0.191919}, {0.270774, 0.582857,
0.261769}, {0.4165, 0.935575, 0.243333}} *)
BoolEval[matrix < 0.5]
{{0, 0, 1}, {1, 0, 1}, {1, 0, 1}}
You can of course replace zeros with False and ones with True (/. {0 -> False, 1 -> True}) but don't do it unless you really need it, because those values are not stored as efficiently internally. If you do that then the list will no longer be "packed".
