Re: ClearAll error message
- To: mathgroup at smc.vnet.net
- Subject: [mg92363] Re: ClearAll error message
- From: Albert Retey <awnl at gmx-topmail.de>
- Date: Mon, 29 Sep 2008 07:06:57 -0400 (EDT)
- References: <gbnpep$pr3$1@smc.vnet.net>
carlos at colorado.edu wrote: > Just out of curiosity. The following ClearAll works as expected. > > name=Symbol["A"]; ClearAll[name]; > > But this elicits an error message: > > ClearAll[Symbol["A"]]; > > Why? A non-standard argument evaluation? Yes, since Clear needs to work with symbols which have a value, it has attribute HoldAll: Attributes[Clear] This should work, provided there is no OwnValue for A: ClearAll[Evaluate[Symbol["A"]]] if you want to be on the save side, you should make it work even if there is an OwnValue for A, which is more elaborate: Apply[ClearAll,ToExpression["A", InputForm, Hold]] hth, albert