Re: problem with append
- To: mathgroup at smc.vnet.net
- Subject: [mg129546] Re: problem with append
- From: Alexei Boulbitch <Alexei.Boulbitch at iee.lu>
- Date: Tue, 22 Jan 2013 02:39:46 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- Delivered-to: l-mathgroup@wolfram.com
- Delivered-to: mathgroup-newout@smc.vnet.net
- Delivered-to: mathgroup-newsend@smc.vnet.net
hello i am new to mathmatica.i have the following problem if anyone could help.
For[a = 2, a < 6, a++,
For[b = 2, b < 6, b++,
Appendto[rr = {}, a^b]]]
rr
but rr remains empty. how can i solve this
thank you
Hi, Paolo,
You have problems with syntax. Instead try this:
Block[{r = {}},
For[a = 2, a < 6, a++, For[b = 2, b < 6, b++, AppendTo[r, a^b]]];
Print[r]
]
{4,8,16,32,9,27,81,243,16,64,256,1024,25,125,625,3125}
Or this:
a = {};
Block[{r = {}},
For[a = 2, a < 6, a++, For[b = 2, b < 6, b++, AppendTo[r, a^b]]];
a = r
]
{4, 8, 16, 32, 9, 27, 81, 243, 16, 64, 256, 1024, 25, 125, 625, 3125}
Take care that it is not "Appendto", but "AppendTo" that is important. However, in Mathematica the utilization of loops is usually discouraged. Use better Table, like this:
Table[i^j, {i, 2, 5}, {j, 2, 5}]
{{4, 8, 16, 32}, {9, 27, 81, 243}, {16, 64, 256, 1024}, {25, 125, 625,
3125}}
Table[i^j, {i, 2, 5}, {j, 2, 5}] // Flatten
{4, 8, 16, 32, 9, 27, 81, 243, 16, 64, 256, 1024, 25, 125, 625, 3125}
Have fun, Alexei
Alexei BOULBITCH, Dr., habil.
IEE S.A.
ZAE Weiergewan,
11, rue Edmond Reuter,
L-5326 Contern, LUXEMBOURG
Office phone : +352-2454-2566
Office fax: +352-2454-3566
mobile phone: +49 151 52 40 66 44
e-mail: alexei.boulbitch at iee.lu