4.3: Selecting Elements
- Page ID
- 84700
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You can select an element from a vector with parentheses:
>> Y = [6 7 8 9]
Y = 6 7 8 9
>> Y(1)
ans = 6
>> Y(4)
ans = 9
This means that the first element of Y
is 6
and the fourth element is 9
. The number in parentheses is called the index because it indicates which element of the vector you want.
The index can be a variable name or a mathematical expression:
>> i = 1;
>> Y(i)
ans = 6
>> Y(i+1)
ans = 7
We can use a loop to display the elements of Y
:
for i=1:4
Y(i)
end
Each time through the loop we use a different value of i
as an index into Y
.
In the previous example we had to know the number of elements in Y
. We can make it more general by using the length
function, which returns the number of elements in a vector:
for i=1:length(Y)
Y(i)
end
This version works for a vector of any length.