Re: search for an operator in an expression

*To*: mathgroup at smc.vnet.net*Subject*: [mg78281] Re: search for an operator in an expression*From*: dh <dh at metrohm.ch>*Date*: Wed, 27 Jun 2007 05:34:51 -0400 (EDT)*References*: <f5iuqu$a99$1@smc.vnet.net> <f5o8jr$5jo$1@smc.vnet.net> <f5qhdc$2jt$1@smc.vnet.net>

Hi, you must distinguish between OutputFormat, what you see, and FullForm, what Mathematica sees. Try: FullForm[yourExpression] then you will see that you have 1 operator Plus with multiple arguments. If you want to see the number of arguments, you could e.g. use: Cases[expression, Plus[x__] :> Length[x]] hope this helps, Daniel 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 >> >> >> >> >