RE: If-statement problems
- To: mathgroup at smc.vnet.net
- Subject: [mg49502] RE: [mg49472] If-statement problems
- From: "Wolf, Hartmut" <Hartmut.Wolf at t-systems.com>
- Date: Thu, 22 Jul 2004 02:45:21 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
>-----Original Message----- >From: Aaron Fude [mailto:aaronfude at yahoo.com] To: mathgroup at smc.vnet.net >Sent: Wednesday, July 21, 2004 12:40 PM >To: mathgroup at smc.vnet.net >Subject: [mg49502] [mg49472] If-statement problems > > >Hi, > >New to Mathematica. I can't figure out how to use the >if-statement for pure >flow control. > >Here's an example: > >A = {5, 6, 7, 8} >For [n = 1, n <= 4, n++, > if [n == 1, a = A[[n]]]; > if [n == 2, b = A[[n]]]; > if [n == 3, c = A[[n]]]; > if [n == 4, d = A[[n]]]; >] > >I want to assign to a b c and d the 4 values from A. >Obviously, that's not >what happens. How do I accomplish what I need? > >Many thanks in advance!!! > >Aaron Fude > > > You may do In[1]:= A = {5, 6, 7, 8}; For[n = 1, n <= 4, n++, If[n == 1, a = A[[n]]]; If[n == 2, b = A[[n]]]; If[n == 3, c = A[[n]]]; If[n == 4, d = A[[n]]];] In[3]:= {a, b, c, d} Out[3]= {5, 6, 7, 8} So it works, if you happen to spell If right. But this certainly isn't the way we do in Mathematica. Observe In[4]:= Clear[a, b, c, d] In[5]:= {a, b, c, d} Out[5]= {a, b, c, d} In[6]:= {a, b, c, d} = A; In[7]:= {a, b, c, d} Out[7]= {5, 6, 7, 8} -- Hartmut