>	# lets talk a bit more about lists: # at fist, here is a range, which is just a sequence:

>

2..3;

>

1..10;

>

10..1

Warning, inserted missing semicolon at end of statement, 10..1;

>	# hmm, we cannot have a "downward range"

>	# this is how we create a sequence:

>	s := seq(i,i=1..10);

>	# same thing, but now as a list

>	s := [seq(i,i=1..10)];

>	# we cannot have a range counting downwards. # for this we seed to use lists.

>

>	# the following piece of code produces a list whose elements are decreasing.

>	[seq(5+1-i,i=1..5)];

>	# yet another way

>	ListTools[Reverse]([seq(i,i=1..5)]);

>	# alternatively, we could have loaded the package # by using with(listtools);

>	# let's use the map command. # The map command applies a function to all elements of a list. # For example, we may increase each element in the list by one # as follows (here we use the function i -> i+1, I hope # you still remember this notation)

>	map( i -> i+1, [seq(i,i=1..5)]);

>	# We may also write the function as a procedure, # using the proc command:

>	map( proc(a) return a + 1; end, [seq(i,i=1..5)]);

>

# a procedure always starts with proc() # in the parenthesis, we may put one or more arguments (or parameter) # for the procedure as input. # the procedure body goes right to the command end which closes the procedure. # we may have a return command inside the procedure, # then the procedure is treated as a function, # namely the function which returns the value from the return command. # So, in this case, we have a procedure which takes as arguments # an integer a and computes a + 1 as return value. # That's all folks!

>	# Let's say we want to add some quantity to all emntries of the list, # but we want to pass the value of that quantity as a parameter # to the procedure. # This is how we do it, we just put that parameter as an additional # argument to the map command.

>	map( proc(a,n) return a+n; end, [seq(i,i=1..5)], 3);

>	# Here 3 is the additional parameter which gets passed as n to out procedure. # In this case, we just want to add 3 to all list elements.

>

>	# OK, now we have another way of creating a list with the numbers downwards

>	map( proc(a,n) return n + 1 - a; end, [seq(i,i=1..5)], 5);

>

>	with(StringTools): Warning, the assiged name Group now has a global binding

Error, missing operator or `;`

>	Map( Capitalize, "This is a test." );

>	Map( LowerCase, %);

>	convert("Test string", 'bytes');

>	convert([65,66,67], 'bytes');

>	convert("abcdefghijklmnopqrstuvwxyz", 'bytes');

>	convert("ABCDEFGHIJKLMNOPQRSTUVWXYZ", 'bytes');

>	convert(" -=!@#$%^&*()_", 'bytes');

>	convert(%,'bytes');

>

>

>	# HOMEWORK

>

# hw 1:

>	# Create a list with the numbers n, n-2, n-4, n-6,...2 for any given even n # a) using a for loop with appending to a list # b) using the seq command # c) using seq and map command using a function (i -> something) # d) using seq and map command using a procedure

>

>

# hw 2:

>	# what is the following procedure doing?

>	par := proc(n,k)  local i;    if n=0 then return([[]]) fi;  map(    proc(i,n)      op(map(        proc(a,b)          [b,op(a)]:        end,        par(n - i,i),        i));    end,    ListTools[Reverse]([ seq(i, i = 1 .. min(n,k)) ]),    n); end:

>

>	# hw 3 # a) Create a 8 by 8 matrix whose (i,j) th entry is the result of par(i,j). # b) Create a 8 by 8 matrix while (i,j) th entry is the length of the list #    in the (i,j) th entry of the matrix from a).

>

>	# hw 4 # write some code which takes as input a string and # which reverses the order of the characters. # i.e. "hallo" should become "ollah"

>

>