Re: Re: search for an operator in an expression

*To*: mathgroup at smc.vnet.net*Subject*: [mg78296] Re: [mg78204] Re: search for an operator in an expression*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Wed, 27 Jun 2007 05:42:32 -0400 (EDT)*References*: <f5iuqu$a99$1@smc.vnet.net> <f5o8jr$5jo$1@smc.vnet.net> <200706260805.EAA02477@smc.vnet.net>

In Mathematica Plus is an n-ary operation, e.g. Plus[a, b, c, d] a + b + c + d So there is only one Plus operator even though you see 4 "pluses". Probably the easiest way to get what you want is simply to count the number of + characters in the expression converted to a string; expr = 2 + a*Exp[-b x] + Sin[c + b] + d; StringCount[ToString[expr], "+"] 4 Andrzej Kozlowski On 26 Jun 2007, at 17:05, rob wrote: > Sir, I tried your suggestion as follows: > > expr = 2 + a*Exp[-b x] + Sin[c + b] + d > > Count[expr, HoldPattern[Plus[__]], Infinity] > > which gives a result of "1". I count 4 "+" in expr. Please, > what am I doing wrong? Thanks. > > dh wrote: > >> Hi Daniel, >> >> you may use "Count". Take care to search on all "levels" and prevent >> >> evaluation of the operator. Asssuming your expression is in: expr, >> e.g.: >> >> Count[expr, HoldPattern[ Plus[__] ], Infinity] >> >> hope this helps, Daniel >> >> >> >> >> >> Daniel wrote: >> >> >>> Is there a way to search for an operator in a symbolic >>> expression? My wish is to show that there is only "+" in a very >>> large expression. Rather than showing an expression on multiple >>> pages I would like to perform a search that shows there is only >>> "+" between the terms. Converting to a string does not seem to >>> work since the expression is written on multiple lines(fractions, >>> exponents etc..) >> >> >> >>> Thanks >> >> >> >> >> >

**References**:**Re: search for an operator in an expression***From:*rob <josh2499@hotmail.com>