## 266 Reputation

19 years, 132 days

## The Selection Operation...

```> lst:=[seq([seq(i+10*j,i=1..5)],j=1..4)];

lst := [[11, 12, 13, 14, 15], [21, 22, 23, 24, 25], [31, 32, 33, 34, 35],

[41, 42, 43, 44, 45]]

> lst[1..,2]; # Take the second column of each row

[12, 22, 32, 42]

```
Regards, -- Jean-Marc

## This occurs only if the...

This occurs only if the identity is on the right-end of an expression that contains more that two elements and is not surrounded by parentheses .
```> restart;
> define('`&*`','multilinear','flat','identity'=1);
> (a &* b) &* c - a &* (b &* c);
0
> a &* 1;
a
> 1 &* a;
a
> 1 &* a &* b;
a &* b
> a &* 1 &* b;
a &* b
> a &* b &* 1;
&*(a, b, 1)
> a &* (b &* 1);
a &* b
```
Regards, -- Jean-Marc

## This occurs only if the...

This occurs only if the identity is on the right-end of an expression that contains more that two elements and is not surrounded by parentheses .
```> restart;
> define('`&*`','multilinear','flat','identity'=1);
> (a &* b) &* c - a &* (b &* c);
0
> a &* 1;
a
> 1 &* a;
a
> 1 &* a &* b;
a &* b
> a &* 1 &* b;
a &* b
> a &* b &* 1;
&*(a, b, 1)
> a &* (b &* 1);
a &* b
```
Regards, -- Jean-Marc

## define() accepts...

define() accepts expressions and procedures in addition to keywords, so the distributivity law of &* over + could be defined as follows:
```> define('`&*`','multilinear',a &* (b + c) = (a &* b) +
(a &* c),'flat','identity'=1);

> x &* (y + z);
x &* y + x &* z

> 2 &* (3 + a);
6 + 2 a

```
Regards, -- Jean-Marc

## define() accepts...

define() accepts expressions and procedures in addition to keywords, so the distributivity law of &* over + could be defined as follows:
```> define('`&*`','multilinear',a &* (b + c) = (a &* b) +
(a &* c),'flat','identity'=1);

> x &* (y + z);
x &* y + x &* z

> 2 &* (3 + a);
6 + 2 a

```
Regards, -- Jean-Marc

## I believe you mean something...

I believe you mean something like that:
```restart;
mu := 5.0; sigma := 2.0;
X1 := RandomTools:-Generate(list(distribution(Normal(mu, sigma)), 1100));
K1 := select(proc (x) options operator, arrow; 0 <= x and mu-3*sigma <= x
and x <= mu+3*sigma end proc, X1)[1 .. 1000];
nops(X1); nops(K1);

1100
1000
```
Regards, -- Jean-Marc

## I believe you mean something...

I believe you mean something like that:
```restart;
mu := 5.0; sigma := 2.0;
X1 := RandomTools:-Generate(list(distribution(Normal(mu, sigma)), 1100));
K1 := select(proc (x) options operator, arrow; 0 <= x and mu-3*sigma <= x
and x <= mu+3*sigma end proc, X1)[1 .. 1000];
nops(X1); nops(K1);

1100
1000
```
Regards, -- Jean-Marc

## You could also use the interactive matri...

You could also use the interactive matrix browser. Regards, -- Jean-Marc

## You could also use the interactive matri...

You could also use the interactive matrix browser. Regards, -- Jean-Marc

## convert(S, list) ?...

Regards, -- Jean-Marc

## convert(S, list) ?...

Regards, -- Jean-Marc

You can find the answers to your questions about Maple syntax and functions in the online help. You can either browse the online documentation or search for specific topic or keywords in the left-hand pane. For instance, type trunc and hit the button labeled "Search". Also, you can access specific pages related to a function by evaluating the question mark operator ? followed by some topic or function name. For instance, will bring you to Regards, -- Jean-Marc