• → Except

Alternatives (|)

WMA link

Alternatives[$p_1$, $p_2$, ..., $p_i$]

$p_1$ | $p_2$ | ... | $p_i$

is a pattern that matches any of the patterns $p_1$, $p_2$, ...., $p_i$.

• • a+b+c+d/.(a|b)->t

Alternatives can also be used for string expressions:

• • StringReplace["0123 3210", "1" | "2" -> "X"]