Re: Head logic
- To: mathgroup at smc.vnet.net
- Subject: [mg97050] Re: [mg97033] Head logic
- From: Sseziwa Mukasa <mukasa at jeol.com>
- Date: Wed, 4 Mar 2009 07:09:55 -0500 (EST)
- References: <200903031055.FAA02912@smc.vnet.net>
On Mar 3, 2009, at 5:55 AM, carlos at colorado.edu wrote: > Entering > > ClearAll[r]; > Head[r] > Head[r]!=Symbol > Head[r]==Symbol > > give Symbol, False and True as expected. But > > Head[r]==Integer > > evaluates to Symbol==Integer. Why not False? > Head[r] is certainly not Integer. Likewise > > r=4; > Head[r]==Integer > Head[r]!=Symbol > Head[r]==Symbol > > give True (correct) but Integer!=Symbol and Integer==Symbol. > Why not True and False? > == only evaluates to False for comparisons between certain types of raw data according to the help documentation, == apparently doesn't evaluate to False for Symbols of different value. You can use === and =!= if this is a problem. Regards, Sseziwa
- References:
- Head logic
- From: carlos@colorado.edu
- Head logic