Re: String[bring] vs "bring"
- To: mathgroup at smc.vnet.net
- Subject: [mg59351] Re: [mg59350] String[bring] vs "bring"
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Sun, 7 Aug 2005 03:46:48 -0400 (EDT)
- References: <200508060530.BAA01232@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
The point is that String[bring] is not an string, just an object with head String. The key difference between it and a real string "bring" is that latter is an atom: AtomQ["bring"] True but AtomQ[String[bring]] False Also, your use of Cases in Cases[ToString[bring], _String] {} fails because Cases looks only at parts of an expression, thus you need to use (for exmple) Cases[{ToString[bring]}, _String] {bring} This, of course, will also work: Cases[{String[bring]}, _String] {String[bring]} but that's just saying that String[bring] has head String. You could do the same with Integer: Cases[{Integer[dog]}, _Integer] {Integer[dog]} But it still does not mean that Integer[dog] is a Mathematica integer. Andrzej Kozlowski On 6 Aug 2005, at 07:30, Kristen W Carlson wrote: > Hi, > > Question: What is the difference between "bring" and String[bring] ? > What is the utility of making them different? > > Question: What is the difference between "bring" and String[bring] ? > What is the utility of making them different? > > "bring" ===String[bring] > > False > > Cases[{"bring"}, _String] > > {bring} > > Cases[String[bring], _String] > > {} > > Cases[ToString[bring], _String] > > {} > > InputForm[String[bring]] > > String[bring] > > InputForm["bring"] > > "bring" > > FullForm[String[bring]] > > String[bring] > > And yet: > > Head["bring"] > > String > > FullForm["bring"] > > "bring" > > ToString[bring] > > bring > > InputForm[%] > > "bring" > > Wha???? > > Thanks, > > Kris > >
- References:
- String[bring] vs "bring"
- From: Kristen W Carlson <carlsonkw@gmail.com>
- String[bring] vs "bring"