• ← Remove

Unset (=.)

WMA link

Unset[x]

x=.

removes any value belonging to x.

• • a = 2

• • a =.

• • a

Unsetting an already unset or never defined variable will not change anything:

• • a =.

• • b =.

Unset can unset particular function values. It will print a message if no corresponding rule is found.

• • f[x_] =.

• • f[x_] := x ^ 2

• • f[3]

• • f[x_] =.

• • f[3]

You can also unset OwnValues, DownValues, SubValues, and UpValues directly. This is equivalent to setting them to {}.

• • f[x_] = x; f[0] = 1;

• • DownValues[f] =.

• • f[2]

Unset threads over lists:

• • a = b = 3;

• • {a, {b}} =.