octave: Comma Separated Lists Generated from Cell Arrays
6.3.1 Comma Separated Lists Generated from Cell Arrays
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As has been mentioned above (
Indexing Cell Arrays), elements of
a cell array can be extracted into a comma separated list with the ‘{’
and ‘}’ operators. By surrounding this list with ‘[’ and ‘]’, it can be
concatenated into an array. For example:
a = {1, [2, 3], 4, 5, 6};
b = [a{1:4}]
⇒ b =
1 2 3 4 5
Similarly, it is possible to create a new cell array containing cell
elements selected with ‘{}’. By surrounding the list with ‘{’ and ‘}’ a
new cell array will be created, as the following example illustrates:
a = {1, rand(2, 2), "three"};
b = { a{ [1, 3] } }
⇒ b =
{
[1,1] = 1
[1,2] = three
}
Furthermore, cell elements (accessed by ‘{}’) can be passed directly
to a function. The list of elements from the cell array will be passed
as an argument list to a given function as if it is called with the
elements as individual arguments. The two calls to ‘printf’ in the
following example are identical but the latter is simpler and can handle
cell arrays of an arbitrary size:
c = {"GNU", "Octave", "is", "Free", "Software"};
printf ("%s ", c{1}, c{2}, c{3}, c{4}, c{5});
⊣ GNU Octave is Free Software
printf ("%s ", c{:});
⊣ GNU Octave is Free Software
If used on the left-hand side of an assignment, a comma separated
list generated with ‘{}’ can be assigned to. An example is
in{1} = [10, 20, 30];
in{2} = inf;
in{3} = "last";
in{4} = "first";
out = cell (4, 1);
[out{1:3}] = in{1 : 3};
[out{4:6}] = in{[1, 2, 4]})
⇒ out =
{
[1,1] =
10 20 30
[2,1] = Inf
[3,1] = last
[4,1] =
10 20 30
[5,1] = Inf
[6,1] = first
}
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octave: Comma Separated Lists
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