Welcome all! ❤️‍🔥 This Monday let us learn about Accessing vector elements in MATLAB.🤟

Many times, we need to access the elements in middle of a vector or matrix. MATLAB provides easy methods to extract out the elements.

Accessing vector elements-

We can access and the vector elements as shown in the example

>> x=[1,2,3,4,0,6];
>> x(5)

ans =

     0

>> x(5)=5;
>> x

x =

     1     2     3     4     5     6

MATLAB also allows us to access many elements at once. The result is a 'n' element vector

>> x=[2,4,6,8];
>> y=x([2,3])

y =

     4     6
>> y=x([1,3,4])

y =

     2     6     8

An alternative may be

>> x=[2,4,6,8];
>> data=1:3;
>> y=x(data)

y =

     2     4     6

We can access the last element of thee vector using the "end" keyword.

>> x=[2,4,6,8];
>> x(end)

ans =

     8

>> x(end-1)

ans =

     6

Accessing matrix values-
Matrix values require both the row and the column number to be accessed

>> x=rand(5,6)

x =

    0.9058    0.2785    0.9706    0.4218    0.0357    0.7431
    0.1270    0.5469    0.9572    0.9157    0.8491    0.3922
    0.9134    0.9575    0.4854    0.7922    0.9340    0.6555
    0.6324    0.9649    0.8003    0.9595    0.6787    0.1712
    0.0975    0.1576    0.1419    0.6557    0.7577    0.7060

>> x(2,3)

ans =

    0.9572

We can also extract a whole matrix using the syntax
x(rows,columns), where rows is an array of rows while columns is array of columns. Here are two examples that will make things very clear.

Note that 2:4 means [2,3,4] while comma separated 2,4 means [2,4]

In order to take an entire column or row, we can just place a semicolon ':' for it. Here is an example-

>> x=rand(5,5)

x =

    0.8314    0.4168    0.0155    0.1981    0.0527
    0.8034    0.6569    0.9841    0.4897    0.7379
    0.0605    0.6280    0.1672    0.3395    0.2691
    0.3993    0.2920    0.1062    0.9516    0.4228
    0.5269    0.4317    0.3724    0.9203    0.5479

>> x(:,3)

ans =

    0.0155
    0.9841
    0.1672
    0.1062
    0.3724

>> x(3,:)

ans =

    0.0605    0.6280    0.1672    0.3395    0.2691

That's all for this week. 🏆 Your comments really motivate me, so for any suggestions or doubts, please comment below 👇, and I will be happy to help 🙂 🎗️ Follow me for updates...
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Bye for now 🖐
Meet you all soon👍

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