Re: replacement x->y except in Exp[x]

*To*: mathgroup at smc.vnet.net*Subject*: [mg110889] Re: replacement x->y except in Exp[x]*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Sat, 10 Jul 2010 04:01:03 -0400 (EDT)

I is not a "symbol"! Head[I] Complex 3+I /. I-> -I 3 + I Head[2] Integer (2/3) /. 2->5 2/3 Please stop beating the dead horse. On 7/8/2010 8:34 PM, AES wrote: > ...Is it ever a good idea to use ReplaceAll to do word-processing-type > "global find and replace" changes like this? > > Lengthy threads on this NG have pointed out the havoc that this can > wreak if the symbol I is among those replaced, particularly if one > attempts to do I -> -I. > > Or is I the _only_ symbol in the entire Mathematica vocabulary that > encounters this difficulty? > > (I really would like to know the answer to this question, even if this > is entirely out of curiosity, not any real need. I've asked it > previously, and never gotten an answer.) -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305