ReplaceIf

Conditionally replaces values in a container.

Syntax

• ReplaceIf(X, p, y[, n])

  • X is a container

  • p is a predicate

  • y is any object

  • n is a positive integer

Description

If X is a container, p a boolean-valued function on X, and y any object, then ReplaceIf(X, p, y) returns X with all elements x for which p(x) is true replaced by y. ReplaceIf(X, p, y, n) replaces elements at level n, with level n = 1 being X itself.

Examples

A ≔ RandomIntMatrix(10, 0, 10)

⎛0  6  2  5  7  9  4  5  3  7⎞
⎜8  5  5  8  2  2  2  9  9  6⎟
⎜0  0  5  6  0  2  2  8  9  4⎟
⎜7  4  0  8  0  9  0  1  3  5⎟
⎜4  1  9  4  9  5  5  0  6  9⎟
⎜8  6  6  2  9  3  6  9  1  6⎟
⎜9  0  2  2  7  7  4  4  1  5⎟
⎜0  2  8  1  6  7  3  2  7  6⎟
⎜6  1  9  6  1  4  1  6  1  0⎟
⎝4  7  7  1  2  4  5  0  3  8⎠

ReplaceIf(A, odd, 0)

⎛0  6  2  0  0  0  4  0  0  0⎞
⎜8  0  0  8  2  2  2  0  0  6⎟
⎜0  0  0  6  0  2  2  8  0  4⎟
⎜0  4  0  8  0  0  0  0  0  0⎟
⎜4  0  0  4  0  0  0  0  6  0⎟
⎜8  6  6  2  0  0  6  0  0  6⎟
⎜0  0  2  2  0  0  4  4  0  0⎟
⎜0  2  8  0  6  0  0  2  0  6⎟
⎜6  0  0  6  0  4  0  6  0  0⎟
⎝4  0  0  0  2  4  0  0  0  8⎠

compute(RandomIntMatrix(4, 1, 10), n, 1, 5)

⎛1  5  9  7⎞  ⎛1  3  1  8⎞  ⎛2  7  6  8⎞  ⎛8  2  2  6⎞  ⎛8  3  4  8⎞
⎜6  9  6  7⎟  ⎜9  9  3  5⎟  ⎜2  7  7  6⎟  ⎜2  2  4  2⎟  ⎜8  1  9  9⎟
⎜4  7  7  2⎟  ⎜1  6  6  9⎟  ⎜3  4  8  9⎟  ⎜9  1  8  1⎟  ⎜8  6  9  7⎟
⎝6  8  9  9⎠  ⎝3  3  5  2⎠  ⎝4  9  4  7⎠  ⎝2  5  9  1⎠  ⎝8  2  4  9⎠

ReplaceIf(ans, odd, 0, 2)

⎛0  0  0  0⎞  ⎛0  0  0  8⎞  ⎛2  0  6  8⎞  ⎛8  2  2  6⎞  ⎛8  0  4  8⎞
⎜6  0  6  0⎟  ⎜0  0  0  0⎟  ⎜2  0  0  6⎟  ⎜2  2  4  2⎟  ⎜8  0  0  0⎟
⎜4  0  0  2⎟  ⎜0  6  6  0⎟  ⎜0  4  8  0⎟  ⎜0  0  8  0⎟  ⎜8  6  0  0⎟
⎝6  8  0  0⎠  ⎝0  0  0  2⎠  ⎝4  0  4  0⎠  ⎝2  0  0  0⎠  ⎝8  2  4  0⎠

See also

• ReplaceAll

• ReplaceEvery